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GPG2(1) |
GNU Privacy Guard 2.2 |
GPG2(1) |
gpg2 - OpenPGP encryption and signing tool
gpg2 [--homedir dir] [--options file]
[options] command [args]
gpg2 is the OpenPGP part of the GNU Privacy Guard (GnuPG). It is a tool
to provide digital encryption and signing services using the OpenPGP standard.
gpg2 features complete key management and all the bells and whistles
you would expect from a full OpenPGP implementation.
There are two main versions of GnuPG: GnuPG 1.x and GnuPG 2.x.
GnuPG 2.x supports modern encryption algorithms and thus should be preferred
over GnuPG 1.x. You only need to use GnuPG 1.x if your platform doesn't
support GnuPG 2.x, or you need support for some features that GnuPG 2.x has
deprecated, e.g., decrypting data created with PGP-2 keys.
In contrast to the standalone command gpg from GnuPG 1.x,
the 2.x version is commonly installed under the name gpg2.
The program returns 0 if there are no severe errors, 1 if at least a signature
was bad, and other error codes for fatal errors.
Note that signature verification requires exact knowledge of what
has been signed and by whom it has been signed. Using only the return code
is thus not an appropriate way to verify a signature by a script. Either
make proper use or the status codes or use the gpgv tool which has
been designed to make signature verification easy for scripts.
Use a good password for your user account and make sure that all security issues
are always fixed on your machine. Also employ diligent physical protection to
your machine. Consider to use a good passphrase as a last resort protection to
your secret key in the case your machine gets stolen. It is important that
your secret key is never leaked. Using an easy to carry around token or
smartcard with the secret key is often a advisable.
If you are going to verify detached signatures, make sure that the
program knows about it; either give both filenames on the command line or
use ‘-’ to specify STDIN.
For scripted or other unattended use of gpg make sure to
use the machine-parseable interface and not the default interface which is
intended for direct use by humans. The machine-parseable interface provides
a stable and well documented API independent of the locale or future changes
of gpg. To enable this interface use the options --with-colons
and --status-fd. For certain operations the option
--command-fd may come handy too. See this man page and the file
‘DETAILS’ for the specification of the interface. Note
that the GnuPG ``info'' pages as well as the PDF version of the GnuPG manual
features a chapter on unattended use of GnuPG. As an alternative the library
GPGME can be used as a high-level abstraction on top of that
interface.
GnuPG tries to be a very flexible implementation of the OpenPGP standard. In
particular, GnuPG implements many of the optional parts of the standard, such
as the SHA-512 hash, and the ZLIB and BZIP2 compression algorithms. It is
important to be aware that not all OpenPGP programs implement these optional
algorithms and that by forcing their use via the --cipher-algo,
--digest-algo, --cert-digest-algo, or --compress-algo
options in GnuPG, it is possible to create a perfectly valid OpenPGP message,
but one that cannot be read by the intended recipient.
There are dozens of variations of OpenPGP programs available, and
each supports a slightly different subset of these optional algorithms. For
example, until recently, no (unhacked) version of PGP supported the BLOWFISH
cipher algorithm. A message using BLOWFISH simply could not be read by a PGP
user. By default, GnuPG uses the standard OpenPGP preferences system that
will always do the right thing and create messages that are usable by all
recipients, regardless of which OpenPGP program they use. Only override this
safe default if you really know what you are doing.
If you absolutely must override the safe default, or if the
preferences on a given key are invalid for some reason, you are far better
off using the --pgp6, --pgp7, or --pgp8 options. These
options are safe as they do not force any particular algorithms in violation
of OpenPGP, but rather reduce the available algorithms to a
"PGP-safe" list.
Commands are not distinguished from options except for the fact that only one
command is allowed. Generally speaking, irrelevant options are silently
ignored, and may not be checked for correctness.
gpg2 may be run with no commands. In this case it will
print a warning perform a reasonable action depending on the type of file it
is given as input (an encrypted message is decrypted, a signature is
verified, a file containing keys is listed, etc.).
If you run into any problems, please add the option
--verbose to the invocation to see more diagnostics.
- --version
- Print the program version and licensing information. Note that you cannot
abbreviate this command.
- --help
- -h
- Print a usage message summarizing the most useful command-line options.
Note that you cannot arbitrarily abbreviate this command (though you can
use its short form -h).
- --warranty
- Print warranty information.
- --dump-options
- Print a list of all available options and commands. Note that you cannot
abbreviate this command.
- --sign
- -s
- Sign a message. This command may be combined with --encrypt (to
sign and encrypt a message), --symmetric (to sign and symmetrically
encrypt a message), or both --encrypt and --symmetric (to
sign and encrypt a message that can be decrypted using a secret key or a
passphrase). The signing key is chosen by default or can be set explicitly
using the --local-user and --default-key options.
- --clear-sign
- --clearsign
- Make a cleartext signature. The content in a cleartext signature is
readable without any special software. OpenPGP software is only needed to
verify the signature. cleartext signatures may modify end-of-line
whitespace for platform independence and are not intended to be
reversible. The signing key is chosen by default or can be set explicitly
using the --local-user and --default-key options.
- --detach-sign
- -b
- Make a detached signature.
- --encrypt
- -e
- Encrypt data to one or more public keys. This command may be combined with
--sign (to sign and encrypt a message), --symmetric (to
encrypt a message that can be decrypted using a secret key or a
passphrase), or --sign and --symmetric together (for a
signed message that can be decrypted using a secret key or a passphrase).
--recipient and related options specify which public keys to use
for encryption.
- --symmetric
- -c
- Encrypt with a symmetric cipher using a passphrase. The default symmetric
cipher used is AES-128, but may be chosen with the --cipher-algo
option. This command may be combined with --sign (for a signed and
symmetrically encrypted message), --encrypt (for a message that may
be decrypted via a secret key or a passphrase), or --sign and
--encrypt together (for a signed message that may be decrypted via
a secret key or a passphrase). gpg2 caches the passphrase used for
symmetric encryption so that a decrypt operation may not require that the
user needs to enter the passphrase. The option --no-symkey-cache
can be used to disable this feature.
- --store
- Store only (make a simple literal data packet).
- --decrypt
- -d
- Decrypt the file given on the command line (or STDIN if no file is
specified) and write it to STDOUT (or the file specified with
--output). If the decrypted file is signed, the signature is also
verified. This command differs from the default operation, as it never
writes to the filename which is included in the file and it rejects files
that don't begin with an encrypted message.
- --verify
- Assume that the first argument is a signed file and verify it without
generating any output. With no arguments, the signature packet is read
from STDIN. If only one argument is given, the specified file is expected
to include a complete signature.
With more than one argument, the first argument should specify
a file with a detached signature and the remaining files should contain
the signed data. To read the signed data from STDIN, use
‘-’ as the second filename. For security reasons, a
detached signature will not read the signed material from STDIN if not
explicitly specified.
Note: If the option --batch is not used, gpg2
may assume that a single argument is a file with a detached signature,
and it will try to find a matching data file by stripping certain
suffixes. Using this historical feature to verify a detached signature
is strongly discouraged; you should always specify the data file
explicitly.
Note: When verifying a cleartext signature, gpg2
verifies only what makes up the cleartext signed data and not any extra
data outside of the cleartext signature or the header lines directly
following the dash marker line. The option --output may be used
to write out the actual signed data, but there are other pitfalls with
this format as well. It is suggested to avoid cleartext signatures in
favor of detached signatures.
Note: Sometimes the use of the gpgv tool is easier than
using the full-fledged gpg with this option. gpgv is
designed to compare signed data against a list of trusted keys and
returns with success only for a good signature. It has its own manual
page.
- --multifile
- This modifies certain other commands to accept multiple files for
processing on the command line or read from STDIN with each filename on a
separate line. This allows for many files to be processed at once.
--multifile may currently be used along with --verify,
--encrypt, and --decrypt. Note that --multifile
--verify may not be used with detached signatures.
- --verify-files
- Identical to --multifile --verify.
- --encrypt-files
- Identical to --multifile --encrypt.
- --decrypt-files
- Identical to --multifile --decrypt.
- --list-keys
- -k
- --list-public-keys
- List the specified keys. If no keys are specified, then all keys from the
configured public keyrings are listed.
Never use the output of this command in scripts or other
programs. The output is intended only for humans and its format is
likely to change. The --with-colons option emits the output in a
stable, machine-parseable format, which is intended for use by scripts
and other programs.
- --list-secret-keys
- -K
- List the specified secret keys. If no keys are specified, then all known
secret keys are listed. A # after the initial tags sec or
ssb means that the secret key or subkey is currently not usable. We
also say that this key has been taken offline (for example, a primary key
can be taken offline by exporting the key using the command
--export-secret-subkeys). A > after these tags indicate
that the key is stored on a smartcard. See also --list-keys.
- --check-signatures
- --check-sigs
- Same as --list-keys, but the key signatures are verified and listed
too. Note that for performance reasons the revocation status of a signing
key is not shown. This command has the same effect as using
--list-keys with --with-sig-check.
The status of the verification is indicated by a flag directly
following the "sig" tag (and thus before the flags described
below. A "!" indicates that the signature has been
successfully verified, a "-" denotes a bad signature and a
"%" is used if an error occurred while checking the signature
(e.g. a non supported algorithm). Signatures where the public key is not
available are not listed; to see their keyids the command
--list-sigs can be used.
For each signature listed, there are several flags in between
the signature status flag and keyid. These flags give additional
information about each key signature. From left to right, they are the
numbers 1-3 for certificate check level (see --ask-cert-level),
"L" for a local or non-exportable signature (see
--lsign-key), "R" for a nonRevocable signature (see the
--edit-key command "nrsign"), "P" for a
signature that contains a policy URL (see --cert-policy-url),
"N" for a signature that contains a notation (see
--cert-notation), "X" for an eXpired signature (see
--ask-cert-expire), and the numbers 1-9 or "T" for 10
and above to indicate trust signature levels (see the --edit-key
command "tsign").
- --locate-keys
- --locate-external-keys
- Locate the keys given as arguments. This command basically uses the same
algorithm as used when locating keys for encryption and may thus be used
to see what keys gpg2 might use. In particular external methods as
defined by --auto-key-locate are used to locate a key if the
arguments comain valid mail addresses. Only public keys are listed.
The variant --locate-external-keys does not consider a
locally existing key and can thus be used to force the refresh of a key
via the defined external methods. If a fingerprint is given and and the
methods defined by --auto-key-locate define LDAP servers, the key is
fetched from these resources; defined non-LDAP keyservers are
skipped.
- --show-keys
- This commands takes OpenPGP keys as input and prints information about
them in the same way the command --list-keys does for locally
stored key. In addition the list options show-unusable-uids,
show-unusable-subkeys, show-notations and
show-policy-urls are also enabled. As usual for automated
processing, this command should be combined with the option
--with-colons.
- --fingerprint
- List all keys (or the specified ones) along with their fingerprints. This
is the same output as --list-keys but with the additional output of
a line with the fingerprint. May also be combined with
--check-signatures. If this command is given twice, the
fingerprints of all secondary keys are listed too. This command also
forces pretty printing of fingerprints if the keyid format has been set to
"none".
- --list-packets
- List only the sequence of packets. This command is only useful for
debugging. When used with option --verbose the actual MPI values
are dumped and not only their lengths. Note that the output of this
command may change with new releases.
- --edit-card
- --card-edit
- Present a menu to work with a smartcard. The subcommand "help"
provides an overview on available commands. For a detailed description,
please see the Card HOWTO at
https://gnupg.org/documentation/howtos.html#GnuPG-cardHOWTO .
- --card-status
- Show the content of the smart card.
- --change-pin
- Present a menu to allow changing the PIN of a smartcard. This
functionality is also available as the subcommand "passwd" with
the --edit-card command.
- --delete-keys name
- Remove key from the public keyring. In batch mode either --yes is
required or the key must be specified by fingerprint. This is a safeguard
against accidental deletion of multiple keys. If the exclamation mark
syntax is used with the fingerprint of a subkey only that subkey is
deleted; if the exclamation mark is used with the fingerprint of the
primary key the entire public key is deleted.
- --delete-secret-keys name
- Remove key from the secret keyring. In batch mode the key must be
specified by fingerprint. The option --yes can be used to advise
gpg-agent not to request a confirmation. This extra pre-caution is done
because gpg2 can't be sure that the secret key (as controlled by
gpg-agent) is only used for the given OpenPGP public key. If the
exclamation mark syntax is used with the fingerprint of a subkey only the
secret part of that subkey is deleted; if the exclamation mark is used
with the fingerprint of the primary key only the secret part of the
primary key is deleted.
- --delete-secret-and-public-key name
- Same as --delete-key, but if a secret key exists, it will be
removed first. In batch mode the key must be specified by fingerprint. The
option --yes can be used to advise gpg-agent not to request a
confirmation.
- --export
- Either export all keys from all keyrings (default keyring and those
registered via option --keyring), or if at least one name is given,
those of the given name. The exported keys are written to STDOUT or to the
file given with option --output. Use together with --armor
to mail those keys.
- --send-keys keyIDs
- Similar to --export but sends the keys to a keyserver. Fingerprints
may be used instead of key IDs. Don't send your complete keyring to a
keyserver --- select only those keys which are new or changed by you. If
no keyIDs are given, gpg2 does nothing.
Take care: Keyservers are by design write only systems and
thus it is not possible to ever delete keys once they have been send to
a keyserver.
- --export-secret-keys
- --export-secret-subkeys
- Same as --export, but exports the secret keys instead. The exported
keys are written to STDOUT or to the file given with option
--output. This command is often used along with the option
--armor to allow for easy printing of the key for paper backup;
however the external tool paperkey does a better job of creating
backups on paper. Note that exporting a secret key can be a security risk
if the exported keys are sent over an insecure channel.
The second form of the command has the special property to
render the secret part of the primary key useless; this is a GNU
extension to OpenPGP and other implementations can not be expected to
successfully import such a key. Its intended use is in generating a full
key with an additional signing subkey on a dedicated machine. This
command then exports the key without the primary key to the main
machine.
GnuPG may ask you to enter the passphrase for the key. This is
required, because the internal protection method of the secret key is
different from the one specified by the OpenPGP protocol.
- --export-ssh-key
- This command is used to export a key in the OpenSSH public key format. It
requires the specification of one key by the usual means and exports the
latest valid subkey which has an authentication capability to STDOUT or to
the file given with option --output. That output can directly be
added to ssh's ‘authorized_key’ file.
By specifying the key to export using a key ID or a
fingerprint suffixed with an exclamation mark (!), a specific subkey or
the primary key can be exported. This does not even require that the key
has the authentication capability flag set.
- --import
- --fast-import
- Import/merge keys. This adds the given keys to the keyring. The fast
version is currently just a synonym.
There are a few other options which control how this command
works. Most notable here is the --import-options merge-only
option which does not insert new keys but does only the merging of new
signatures, user-IDs and subkeys.
- --receive-keys keyIDs
- --recv-keys keyIDs
- Import the keys with the given keyIDs from a keyserver.
- --refresh-keys
- Request updates from a keyserver for keys that already exist on the local
keyring. This is useful for updating a key with the latest signatures,
user IDs, etc. Calling this with no arguments will refresh the entire
keyring.
- --search-keys names
- Search the keyserver for the given names. Multiple names given here
will be joined together to create the search string for the keyserver.
Note that keyservers search for names in a different and simpler
way than gpg does. The best choice is to use a mail address. Due to data
privacy reasons keyservers may even not even allow searching by user id or
mail address and thus may only return results when being used with the
--recv-key command to search by key fingerprint or keyid.
- --fetch-keys URIs
- Retrieve keys located at the specified URIs. Note that different
installations of GnuPG may support different protocols (HTTP, FTP, LDAP,
etc.). When using HTTPS the system provided root certificates are used by
this command.
- --update-trustdb
- Do trust database maintenance. This command iterates over all keys and
builds the Web of Trust. This is an interactive command because it may
have to ask for the "ownertrust" values for keys. The user has
to give an estimation of how far she trusts the owner of the displayed key
to correctly certify (sign) other keys. GnuPG only asks for the ownertrust
value if it has not yet been assigned to a key. Using the
--edit-key menu, the assigned value can be changed at any time.
- --check-trustdb
- Do trust database maintenance without user interaction. From time to time
the trust database must be updated so that expired keys or signatures and
the resulting changes in the Web of Trust can be tracked. Normally, GnuPG
will calculate when this is required and do it automatically unless
--no-auto-check-trustdb is set. This command can be used to force a
trust database check at any time. The processing is identical to that of
--update-trustdb but it skips keys with a not yet defined
"ownertrust".
For use with cron jobs, this command can be used together with
--batch in which case the trust database check is done only if a
check is needed. To force a run even in batch mode add the option
--yes.
- --export-ownertrust
- Send the ownertrust values to STDOUT. This is useful for backup purposes
as these values are the only ones which can't be re-created from a
corrupted trustdb. Example:
gpg2 --export-ownertrust > otrust.txt
- --import-ownertrust
- Update the trustdb with the ownertrust values stored in files (or
STDIN if not given); existing values will be overwritten. In case of a
severely damaged trustdb and if you have a recent backup of the ownertrust
values (e.g. in the file ‘otrust.txt’), you may
re-create the trustdb using these commands:
cd ~/.gnupg
rm trustdb.gpg
gpg2 --import-ownertrust < otrust.txt
- --rebuild-keydb-caches
- When updating from version 1.0.6 to 1.0.7 this command should be used to
create signature caches in the keyring. It might be handy in other
situations too.
- --print-md algo
- --print-mds
- Print message digest of algorithm algo for all given files or
STDIN. With the second form (or a deprecated "*" for
algo) digests for all available algorithms are printed.
- --gen-random 0|1|2 count
- Emit count random bytes of the given quality level 0, 1 or 2. If
count is not given or zero, an endless sequence of random bytes
will be emitted. If used with --armor the output will be base64
encoded. PLEASE, don't use this command unless you know what you are
doing; it may remove precious entropy from the system!
- --gen-prime mode bits
- Use the source, Luke :-). The output format is subject to change with ant
release.
- --enarmor
- --dearmor
- Pack or unpack an arbitrary input into/from an OpenPGP ASCII armor. This
is a GnuPG extension to OpenPGP and in general not very useful.
- --unwrap
- This command is similar to --decrypt with the change that the
output is not the usual plaintext but the original message with the
decryption layer removed. Thus the output will be an OpenPGP data
structure which often means a signed OpenPGP message. Note that this
command may or may not remove a compression layer which is often found
beneath the encryption layer.
- --tofu-policy {auto|good|unknown|bad|ask} keys
- Set the TOFU policy for all the bindings associated with the specified
keys. For more information about the meaning of the policies, see:
[trust-model-tofu]. The keys may be specified either by their
fingerprint (preferred) or their keyid.
This section explains the main commands for key management.
- --quick-generate-key user-id [algo [usage
[expire]]]
- --quick-gen-key
- This is a simple command to generate a standard key with one user id. In
contrast to --generate-key the key is generated directly without
the need to answer a bunch of prompts. Unless the option --yes is
given, the key creation will be canceled if the given user id already
exists in the keyring.
If invoked directly on the console without any special options
an answer to a ``Continue?'' style confirmation prompt is required. In
case the user id already exists in the keyring a second prompt to force
the creation of the key will show up.
If algo or usage are given, only the primary key
is created and no prompts are shown. To specify an expiration date but
still create a primary and subkey use ``default'' or ``future-default''
for algo and ``default'' for usage. For a description of
these optional arguments see the command --quick-add-key. The
usage accepts also the value ``cert'' which can be used to create
a certification only primary key; the default is to a create
certification and signing key.
The expire argument can be used to specify an
expiration date for the key. Several formats are supported; commonly the
ISO formats ``YYYY-MM-DD'' or ``YYYYMMDDThhmmss'' are used. To make the
key expire in N seconds, N days, N weeks, N months, or N years use
``seconds=N'', ``Nd'', ``Nw'', ``Nm'', or ``Ny'' respectively. Not
specifying a value, or using ``-'' results in a key expiring in a
reasonable default interval. The values ``never'', ``none'' can be used
for no expiration date.
If this command is used with --batch,
--pinentry-mode has been set to loopback, and one of the
passphrase options (--passphrase, --passphrase-fd, or
--passphrase-file) is used, the supplied passphrase is used for
the new key and the agent does not ask for it. To create a key without
any protection --passphrase '' may be used.
To create an OpenPGP key from the keys available on the
currently inserted smartcard, the special string ``card'' can be used
for algo. If the card features an encryption and a signing key,
gpg will figure them out and creates an OpenPGP key consisting of the
usual primary key and one subkey. This works only with certain
smartcards. Note that the interactive --full-gen-key command
allows to do the same but with greater flexibility in the selection of
the smartcard keys.
Note that it is possible to create a primary key and a subkey
using non-default algorithms by using ``default'' and changing the
default parameters using the option --default-new-key-algo.
- --quick-set-expire fpr expire [*|subfprs]
- With two arguments given, directly set the expiration time of the primary
key identified by fpr to expire. To remove the expiration
time 0 can be used. With three arguments and the third given as an
asterisk, the expiration time of all non-revoked and not yet expired
subkeys are set to expire. With more than two arguments and a list
of fingerprints given for subfprs, all non-revoked subkeys matching
these fingerprints are set to expire.
- --quick-add-key fpr [algo [usage
[expire]]]
- Directly add a subkey to the key identified by the fingerprint fpr.
Without the optional arguments an encryption subkey is added. If any of
the arguments are given a more specific subkey is added.
algo may be any of the supported algorithms or curve
names given in the format as used by key listings. To use the default
algorithm the string ``default'' or ``-'' can be used. Supported
algorithms are ``rsa'', ``dsa'', ``elg'', ``ed25519'', ``cv25519'', and
other ECC curves. For example the string ``rsa'' adds an RSA key with
the default key length; a string ``rsa4096'' requests that the key
length is 4096 bits. The string ``future-default'' is an alias for the
algorithm which will likely be used as default algorithm in future
versions of gpg. To list the supported ECC curves the command gpg
--with-colons --list-config curve can be used.
Depending on the given algo the subkey may either be an
encryption subkey or a signing subkey. If an algorithm is capable of
signing and encryption and such a subkey is desired, a usage
string must be given. This string is either ``default'' or ``-'' to keep
the default or a comma delimited list (or space delimited list) of
keywords: ``sign'' for a signing subkey, ``auth'' for an authentication
subkey, and ``encr'' for an encryption subkey (``encrypt'' can be used
as alias for ``encr''). The valid combinations depend on the
algorithm.
The expire argument can be used to specify an
expiration date for the key. Several formats are supported; commonly the
ISO formats ``YYYY-MM-DD'' or ``YYYYMMDDThhmmss'' are used. To make the
key expire in N seconds, N days, N weeks, N months, or N years use
``seconds=N'', ``Nd'', ``Nw'', ``Nm'', or ``Ny'' respectively. Not
specifying a value, or using ``-'' results in a key expiring in a
reasonable default interval. The values ``never'', ``none'' can be used
for no expiration date.
- --generate-key
- --gen-key
- Generate a new key pair using the current default parameters. This is the
standard command to create a new key. In addition to the key a revocation
certificate is created and stored in the
‘openpgp-revocs.d’ directory below the GnuPG home
directory.
- --full-generate-key
- --full-gen-key
- Generate a new key pair with dialogs for all options. This is an extended
version of --generate-key.
There is also a feature which allows you to create keys in
batch mode. See the manual section ``Unattended key generation'' on how
to use this.
- --generate-revocation name
- --gen-revoke name
- Generate a revocation certificate for the complete key. To only revoke a
subkey or a key signature, use the --edit command.
This command merely creates the revocation certificate so that
it can be used to revoke the key if that is ever needed. To actually
revoke a key the created revocation certificate needs to be merged with
the key to revoke. This is done by importing the revocation certificate
using the --import command. Then the revoked key needs to be
published, which is best done by sending the key to a keyserver (command
--send-key) and by exporting (--export) it to a file which
is then send to frequent communication partners.
- --generate-designated-revocation name
- --desig-revoke name
- Generate a designated revocation certificate for a key. This allows a user
(with the permission of the keyholder) to revoke someone else's key.
- --edit-key
- Present a menu which enables you to do most of the key management related
tasks. It expects the specification of a key on the command line.
- uid n
- Toggle selection of user ID or photographic user ID with index n.
Use * to select all and 0 to deselect all.
- key n
- Toggle selection of subkey with index n or key ID n. Use
* to select all and 0 to deselect all.
- sign
- Make a signature on key of user name. If the key is not yet signed
by the default user (or the users given with -u), the program
displays the information of the key again, together with its fingerprint
and asks whether it should be signed. This question is repeated for all
users specified with -u.
- lsign
- Same as "sign" but the signature is marked as non-exportable and
will therefore never be used by others. This may be used to make keys
valid only in the local environment.
- nrsign
- Same as "sign" but the signature is marked as non-revocable and
can therefore never be revoked.
- tsign
- Make a trust signature. This is a signature that combines the notions of
certification (like a regular signature), and trust (like the
"trust" command). It is generally only useful in distinct
communities or groups. For more information please read the sections
``Trust Signature'' and ``Regular Expression'' in RFC-4880.
Note that "l" (for local / non-exportable),
"nr" (for non-revocable, and "t" (for trust) may be freely
mixed and prefixed to "sign" to create a signature of any type
desired.
If the option --only-sign-text-ids is specified, then any
non-text based user ids (e.g., photo IDs) will not be selected for
signing.
- delsig
- Delete a signature. Note that it is not possible to retract a signature,
once it has been send to the public (i.e. to a keyserver). In that case
you better use revsig.
- revsig
- Revoke a signature. For every signature which has been generated by one of
the secret keys, GnuPG asks whether a revocation certificate should be
generated.
- check
- Check the signatures on all selected user IDs. With the extra option
selfsig only self-signatures are shown.
- adduid
- Create an additional user ID.
- addphoto
- Create a photographic user ID. This will prompt for a JPEG file that will
be embedded into the user ID. Note that a very large JPEG will make for a
very large key. Also note that some programs will display your JPEG
unchanged (GnuPG), and some programs will scale it to fit in a dialog box
(PGP).
- showphoto
- Display the selected photographic user ID.
- deluid
- Delete a user ID or photographic user ID. Note that it is not possible to
retract a user id, once it has been send to the public (i.e. to a
keyserver). In that case you better use revuid.
- revuid
- Revoke a user ID or photographic user ID.
- primary
- Flag the current user id as the primary one, removes the primary user id
flag from all other user ids and sets the timestamp of all affected
self-signatures one second ahead. Note that setting a photo user ID as
primary makes it primary over other photo user IDs, and setting a regular
user ID as primary makes it primary over other regular user IDs.
- keyserver
- Set a preferred keyserver for the specified user ID(s). This allows other
users to know where you prefer they get your key from. See
--keyserver-options honor-keyserver-url for more on how this works.
Setting a value of "none" removes an existing preferred
keyserver.
- notation
- Set a name=value notation for the specified user ID(s). See
--cert-notation for more on how this works. Setting a value of
"none" removes all notations, setting a notation prefixed with a
minus sign (-) removes that notation, and setting a notation name (without
the =value) prefixed with a minus sign removes all notations with that
name.
- pref
- List preferences from the selected user ID. This shows the actual
preferences, without including any implied preferences.
- showpref
- More verbose preferences listing for the selected user ID. This shows the
preferences in effect by including the implied preferences of 3DES
(cipher), SHA-1 (digest), and Uncompressed (compression) if they are not
already included in the preference list. In addition, the preferred
keyserver and signature notations (if any) are shown.
- setpref string
- Set the list of user ID preferences to string for all (or just the
selected) user IDs. Calling setpref with no arguments sets the preference
list to the default (either built-in or set via
--default-preference-list), and calling setpref with
"none" as the argument sets an empty preference list. Use
gpg2 --version to get a list of available algorithms. Note
that while you can change the preferences on an attribute user ID (aka
"photo ID"), GnuPG does not select keys via attribute user IDs
so these preferences will not be used by GnuPG.
When setting preferences, you should list the algorithms in
the order which you'd like to see them used by someone else when
encrypting a message to your key. If you don't include 3DES, it will be
automatically added at the end. Note that there are many factors that go
into choosing an algorithm (for example, your key may not be the only
recipient), and so the remote OpenPGP application being used to send to
you may or may not follow your exact chosen order for a given message.
It will, however, only choose an algorithm that is present on the
preference list of every recipient key. See also the INTEROPERABILITY
WITH OTHER OPENPGP PROGRAMS section below.
- addkey
- Add a subkey to this key.
- addcardkey
- Generate a subkey on a card and add it to this key.
- keytocard
- Transfer the selected secret subkey (or the primary key if no subkey has
been selected) to a smartcard. The secret key in the keyring will be
replaced by a stub if the key could be stored successfully on the card and
you use the save command later. Only certain key types may be transferred
to the card. A sub menu allows you to select on what card to store the
key. Note that it is not possible to get that key back from the card - if
the card gets broken your secret key will be lost unless you have a backup
somewhere.
- bkuptocard file
- Restore the given file to a card. This command may be used to
restore a backup key (as generated during card initialization) to a new
card. In almost all cases this will be the encryption key. You should use
this command only with the corresponding public key and make sure that the
file given as argument is indeed the backup to restore. You should then
select 2 to restore as encryption key. You will first be asked to enter
the passphrase of the backup key and then for the Admin PIN of the card.
- keytotpm
- Transfer the selected secret subkey (or the primary key if no subkey has
been selected) to TPM form. The secret key in the keyring will be replaced
by the TPM representation of that key, which can only be read by the
particular TPM that created it (so the keyfile now becomes locked to the
laptop containing the TPM). Only certain key types may be transferred to
the TPM (all TPM 2.0 systems are mandated to have the rsa2048 and nistp256
algorithms but newer TPMs may have more). Note that the key itself is not
transferred into the TPM, merely encrypted by the TPM in-place, so if the
keyfile is deleted, the key will be lost. Once transferred to TPM
representation, the key file can never be converted back to non-TPM form
and the key will die when the TPM does, so you should first have a backup
on secure offline storage of the actual secret key file before conversion.
It is essential to use the physical system TPM that you have rw permission
on the TPM resource manager device (/dev/tpmrm0). Usually this means you
must be a member of the tss group.
- delkey
- Remove a subkey (secondary key). Note that it is not possible to retract a
subkey, once it has been send to the public (i.e. to a keyserver). In that
case you better use revkey. Also note that this only deletes the
public part of a key.
- revkey
- Revoke a subkey.
- expire
- Change the key or subkey expiration time. If a subkey is selected, the
expiration time of this subkey will be changed. With no selection, the key
expiration of the primary key is changed.
- trust
- Change the owner trust value for the key. This updates the trust-db
immediately and no save is required.
- disable
- enable
- Disable or enable an entire key. A disabled key can not normally be used
for encryption.
- addrevoker
- Add a designated revoker to the key. This takes one optional argument:
"sensitive". If a designated revoker is marked as sensitive, it
will not be exported by default (see export-options).
- passwd
- Change the passphrase of the secret key.
- toggle
- This is dummy command which exists only for backward compatibility.
- clean
- Compact (by removing all signatures except the selfsig) any user ID that
is no longer usable (e.g. revoked, or expired). Then, remove any
signatures that are not usable by the trust calculations. Specifically,
this removes any signature that does not validate, any signature that is
superseded by a later signature, revoked signatures, and signatures issued
by keys that are not present on the keyring.
- minimize
- Make the key as small as possible. This removes all signatures from each
user ID except for the most recent self-signature.
- change-usage
- Change the usage flags (capabilities) of the primary key or of subkeys.
These usage flags (e.g. Certify, Sign, Authenticate, Encrypt) are set
during key creation. Sometimes it is useful to have the opportunity to
change them (for example to add Authenticate) after they have been
created. Please take care when doing this; the allowed usage flags depend
on the key algorithm.
- cross-certify
- Add cross-certification signatures to signing subkeys that may not
currently have them. Cross-certification signatures protect against a
subtle attack against signing subkeys. See
--require-cross-certification. All new keys generated have this
signature by default, so this command is only useful to bring older keys
up to date.
- save
- Save all changes to the keyring and quit.
- quit
- Quit the program without updating the keyring.
The listing shows you the key with its secondary keys and
all user IDs. The primary user ID is indicated by a dot, and selected keys or
user IDs are indicated by an asterisk. The trust value is displayed with the
primary key: "trust" is the assigned owner trust and
"validity" is the calculated validity of the key. Validity values
are also displayed for all user IDs. For possible values of trust, see:
[trust-values].
- --sign-key name
- Signs a public key with your secret key. This is a shortcut version of the
subcommand "sign" from --edit-key.
- --lsign-key name
- Signs a public key with your secret key but marks it as non-exportable.
This is a shortcut version of the subcommand "lsign" from
--edit-key.
- --quick-sign-key fpr [names]
- --quick-lsign-key fpr [names]
- Directly sign a key from the passphrase without any further user
interaction. The fpr must be the verified primary fingerprint of a
key in the local keyring. If no names are given, all useful user
ids are signed; with given [names] only useful user ids matching
one of these names are signed. By default, or if a name is prefixed with a
'*', a case insensitive substring match is used. If a name is prefixed
with a '=' a case sensitive exact match is done.
The command --quick-lsign-key marks the signatures as
non-exportable. If such a non-exportable signature already exists the
--quick-sign-key turns it into a exportable signature. If you
need to update an existing signature, for example to add or change
notation data, you need to use the option --force-sign-key.
This command uses reasonable defaults and thus does not
provide the full flexibility of the "sign" subcommand from
--edit-key. Its intended use is to help unattended key signing by
utilizing a list of verified fingerprints.
- --quick-add-uid user-id new-user-id
- This command adds a new user id to an existing key. In contrast to the
interactive sub-command adduid of --edit-key the
new-user-id is added verbatim with only leading and trailing white
space removed, it is expected to be UTF-8 encoded, and no checks on its
form are applied.
- --quick-revoke-uid user-id user-id-to-revoke
- This command revokes a user ID on an existing key. It cannot be used to
revoke the last user ID on key (some non-revoked user ID must remain),
with revocation reason ``User ID is no longer valid''. If you want to
specify a different revocation reason, or to supply supplementary
revocation text, you should use the interactive sub-command revuid
of --edit-key.
- --quick-revoke-sig fpr signing-fpr
[names]
- This command revokes the key signatures made by signing-fpr from
the key specified by the fingerprint fpr. With names given
only the signatures on user ids of the key matching any of the given names
are affected (see --quick-sign-key). If a revocation already exists
a notice is printed instead of creating a new revocation; no error is
returned in this case. Note that key signature revocations may be
superseded by a newer key signature and in turn again revoked.
- --quick-set-primary-uid user-id primary-user-id
- This command sets or updates the primary user ID flag on an existing key.
user-id specifies the key and primary-user-id the user ID
which shall be flagged as the primary user ID. The primary user ID flag is
removed from all other user ids and the timestamp of all affected
self-signatures is set one second ahead.
- --change-passphrase user-id
- --passwd user-id
- Change the passphrase of the secret key belonging to the certificate
specified as user-id. This is a shortcut for the sub-command
passwd of the --edit-key menu. When using together with the
option --dry-run this will not actually change the passphrase but
check that the current passphrase is correct.
gpg2 features a bunch of options to control the exact behaviour and to
change the default configuration.
Long options can be put in an options file (default
"~/.gnupg/gpg.conf"). Short option names will not work - for
example, "armor" is a valid option for the options file, while
"a" is not. Do not write the 2 dashes, but simply the name of the
option and any required arguments. Lines with a hash ('#') as the first
non-white-space character are ignored. Commands may be put in this file too,
but that is not generally useful as the command will execute automatically
with every execution of gpg.
Please remember that option parsing stops as soon as a non-option
is encountered, you can explicitly stop parsing by using the special option
--.
These options are used to change the configuration and most of
them are usually found in the option file.
- --default-key name
- Use name as the default key to sign with. If this option is not
used, the default key is the first key found in the secret keyring. Note
that -u or --local-user overrides this option. This option
may be given multiple times. In this case, the last key for which a secret
key is available is used. If there is no secret key available for any of
the specified values, GnuPG will not emit an error message but continue as
if this option wasn't given.
- --default-recipient name
- Use name as default recipient if option --recipient is not
used and don't ask if this is a valid one. name must be non-empty.
- --default-recipient-self
- Use the default key as default recipient if option --recipient is
not used and don't ask if this is a valid one. The default key is the
first one from the secret keyring or the one set with
--default-key.
- --no-default-recipient
- Reset --default-recipient and --default-recipient-self.
Should not be used in an option file.
- -v, --verbose
- Give more information during processing. If used twice, the input data is
listed in detail.
- --no-verbose
- Reset verbose level to 0. Should not be used in an option file.
- -q, --quiet
- Try to be as quiet as possible. Should not be used in an option file.
- --batch
- --no-batch
- Use batch mode. Never ask, do not allow interactive commands.
--no-batch disables this option. Note that even with a filename
given on the command line, gpg might still need to read from STDIN (in
particular if gpg figures that the input is a detached signature and no
data file has been specified). Thus if you do not want to feed data via
STDIN, you should connect STDIN to ‘/dev/null’.
It is highly recommended to use this option along with the
options --status-fd and --with-colons for any unattended
use of gpg. Should not be used in an option file.
- --no-tty
- Make sure that the TTY (terminal) is never used for any output. This
option is needed in some cases because GnuPG sometimes prints warnings to
the TTY even if --batch is used.
- --yes
- Assume "yes" on most questions. Should not be used in an option
file.
- --no
- Assume "no" on most questions. Should not be used in an option
file.
- --list-options parameters
- This is a space or comma delimited string that gives options used when
listing keys and signatures (that is, --list-keys,
--check-signatures, --list-public-keys,
--list-secret-keys, and the --edit-key functions). Options
can be prepended with a no- (after the two dashes) to give the
opposite meaning. The options are:
- show-photos
- Causes --list-keys, --check-signatures,
--list-public-keys, and --list-secret-keys to display any
photo IDs attached to the key. Defaults to no. See also
--photo-viewer. Does not work with --with-colons: see
--attribute-fd for the appropriate way to get photo data for
scripts and other frontends.
- show-usage
- Show usage information for keys and subkeys in the standard key listing.
This is a list of letters indicating the allowed usage for a key
(E=encryption, S=signing, C=certification,
A=authentication). Defaults to yes.
- show-policy-urls
- Show policy URLs in the --check-signatures listings. Defaults to
no.
- show-notations
- show-std-notations
- show-user-notations
- Show all, IETF standard, or user-defined signature notations in the
--check-signatures listings. Defaults to no.
- show-keyserver-urls
- Show any preferred keyserver URL in the --check-signatures
listings. Defaults to no.
- show-uid-validity
- Display the calculated validity of user IDs during key listings. Defaults
to yes.
- show-unusable-uids
- Show revoked and expired user IDs in key listings. Defaults to no.
- show-unusable-subkeys
- Show revoked and expired subkeys in key listings. Defaults to no.
- show-keyring
- Display the keyring name at the head of key listings to show which keyring
a given key resides on. Defaults to no.
- show-sig-expire
- Show signature expiration dates (if any) during --check-signatures
listings. Defaults to no.
- show-sig-subpackets
- Include signature subpackets in the key listing. This option can take an
optional argument list of the subpackets to list. If no argument is
passed, list all subpackets. Defaults to no. This option is only
meaningful when using --with-colons along with
--check-signatures.
- show-only-fpr-mbox
- For each user-id which has a valid mail address print only the fingerprint
followed by the mail address.
- sort-sigs
- With --list-sigs and --check-sigs sort the signatures by keyID and
creation time to make it easier to view the history of these signatures.
The self-signature is also listed before other signatures. Defaults to
yes.
- --verify-options parameters
- This is a space or comma delimited string that gives options used when
verifying signatures. Options can be prepended with a `no-' to give the
opposite meaning. The options are:
- show-photos
- Display any photo IDs present on the key that issued the signature.
Defaults to no. See also --photo-viewer.
- show-policy-urls
- Show policy URLs in the signature being verified. Defaults to yes.
- show-notations
- show-std-notations
- show-user-notations
- Show all, IETF standard, or user-defined signature notations in the
signature being verified. Defaults to IETF standard.
- show-keyserver-urls
- Show any preferred keyserver URL in the signature being verified. Defaults
to yes.
- show-uid-validity
- Display the calculated validity of the user IDs on the key that issued the
signature. Defaults to yes.
- show-unusable-uids
- Show revoked and expired user IDs during signature verification. Defaults
to no.
- show-primary-uid-only
- Show only the primary user ID during signature verification. That is all
the AKA lines as well as photo Ids are not shown with the signature
verification status.
- --enable-large-rsa
- --disable-large-rsa
- With --generate-key and --batch, enable the creation of RSA secret keys as
large as 8192 bit. Note: 8192 bit is more than is generally recommended.
These large keys don't significantly improve security, but they are more
expensive to use, and their signatures and certifications are larger. This
option is only available if the binary was build with large-secmem
support.
- --enable-dsa2
- --disable-dsa2
- Enable hash truncation for all DSA keys even for old DSA Keys up to 1024
bit. This is also the default with --openpgp. Note that older
versions of GnuPG also required this flag to allow the generation of DSA
larger than 1024 bit.
- --photo-viewer string
- This is the command line that should be run to view a photo ID.
"%i" will be expanded to a filename containing the photo.
"%I" does the same, except the file will not be deleted once the
viewer exits. Other flags are "%k" for the key ID,
"%K" for the long key ID, "%f" for the key
fingerprint, "%t" for the extension of the image type (e.g.
"jpg"), "%T" for the MIME type of the image (e.g.
"image/jpeg"), "%v" for the single-character
calculated validity of the image being viewed (e.g. "f"),
"%V" for the calculated validity as a string (e.g.
"full"), "%U" for a base32 encoded hash of the user
ID, and "%%" for an actual percent sign. If neither %i or %I are
present, then the photo will be supplied to the viewer on standard input.
On Unix the default viewer is xloadimage -fork -quiet
-title 'KeyID 0x%k' STDIN with a fallback to display -title
'KeyID 0x%k' %i and finally to xdg-open %i. On Windows
!ShellExecute 400 %i is used; here the command is a meta command
to use that API call followed by a wait time in milliseconds which is
used to give the viewer time to read the temporary image file before gpg
deletes it again. Note that if your image viewer program is not secure,
then executing it from gpg does not make it secure.
- --exec-path string
- Sets a list of directories to search for photo viewers If not provided
photo viewers use the PATH environment variable.
- --keyring file
- Add file to the current list of keyrings. If file begins
with a tilde and a slash, these are replaced by the $HOME directory. If
the filename does not contain a slash, it is assumed to be in the GnuPG
home directory ("~/.gnupg" unless --homedir or $GNUPGHOME
is used).
Note that this adds a keyring to the current list. If the
intent is to use the specified keyring alone, use --keyring along
with --no-default-keyring.
If the option --no-keyring has been used no keyrings
will be used at all.
Note that if the option use-keyboxd is enabled in
‘common.conf’, no keyrings are used at all and keys
are all maintained by the keyboxd process in its own database.
- --primary-keyring file
- This is a varian of --keyring and designates file as the
primary public keyring. This means that newly imported keys (via
--import or keyserver --recv-from) will go to this keyring.
- --secret-keyring file
- This is an obsolete option and ignored. All secret keys are stored in the
‘private-keys-v1.d’ directory below the GnuPG home
directory.
- --trustdb-name file
- Use file instead of the default trustdb. If file begins with
a tilde and a slash, these are replaced by the $HOME directory. If the
filename does not contain a slash, it is assumed to be in the GnuPG home
directory (‘~/.gnupg’ if --homedir or
$GNUPGHOME is not used).
- --homedir dir
- Set the name of the home directory to dir. If this option is not
used, the home directory defaults to ‘~/.gnupg’. It
is only recognized when given on the command line. It also overrides any
home directory stated through the environment variable
‘GNUPGHOME’ or (on Windows systems) by means of the
Registry entry HKCU\Software\GNU\GnuPG:HomeDir.
On Windows systems it is possible to install GnuPG as a
portable application. In this case only this command line option is
considered, all other ways to set a home directory are ignored.
To install GnuPG as a portable application under Windows,
create an empty file named ‘gpgconf.ctl’ in the
same directory as the tool ‘gpgconf.exe’. The root
of the installation is then that directory; or, if
‘gpgconf.exe’ has been installed directly below a
directory named ‘bin’, its parent directory. You
also need to make sure that the following directories exist and are
writable: ‘ROOT/home’ for the GnuPG home and
‘ROOT/var/cache/gnupg’ for internal cache
files.
- --display-charset name
- Set the name of the native character set. This is used to convert some
informational strings like user IDs to the proper UTF-8 encoding. Note
that this has nothing to do with the character set of data to be encrypted
or signed; GnuPG does not recode user-supplied data. If this option is not
used, the default character set is determined from the current locale. A
verbosity level of 3 shows the chosen set. This option should not be used
on Windows. Valid values for name are:
- iso-8859-1
- This is the Latin 1 set.
- iso-8859-2
- The Latin 2 set.
- iso-8859-15
- This is currently an alias for the Latin 1 set.
- koi8-r
- The usual Russian set (RFC-1489).
- utf-8
- Bypass all translations and assume that the OS uses native UTF-8
encoding.
- --utf8-strings
- --no-utf8-strings
- Assume that command line arguments are given as UTF-8 strings. The default
(--no-utf8-strings) is to assume that arguments are encoded in the
character set as specified by --display-charset. These options
affect all following arguments. Both options may be used multiple times.
This option should not be used in an option file.
This option has no effect on Windows. There the internal used
UTF-8 encoding is translated for console input and output. The command
line arguments are expected as Unicode and translated to UTF-8. Thus
when calling this program from another, make sure to use the Unicode
version of CreateProcess.
- --options file
- Read options from file and do not try to read them from the default
options file in the homedir (see --homedir). This option is ignored
if used in an options file.
- --no-options
- Shortcut for --options /dev/null. This option is detected before an
attempt to open an option file. Using this option will also prevent the
creation of a ‘~/.gnupg’ homedir.
- -z n
- --compress-level n
- --bzip2-compress-level n
- Set compression level to n for the ZIP and ZLIB compression
algorithms. The default is to use the default compression level of zlib
(normally 6). --bzip2-compress-level sets the compression level for
the BZIP2 compression algorithm (defaulting to 6 as well). This is a
different option from --compress-level since BZIP2 uses a
significant amount of memory for each additional compression level.
-z sets both. A value of 0 for n disables compression.
- --bzip2-decompress-lowmem
- Use a different decompression method for BZIP2 compressed files. This
alternate method uses a bit more than half the memory, but also runs at
half the speed. This is useful under extreme low memory circumstances when
the file was originally compressed at a high
--bzip2-compress-level.
- --mangle-dos-filenames
- --no-mangle-dos-filenames
- Older version of Windows cannot handle filenames with more than one dot.
--mangle-dos-filenames causes GnuPG to replace (rather than add to)
the extension of an output filename to avoid this problem. This option is
off by default and has no effect on non-Windows platforms.
- --ask-cert-level
- --no-ask-cert-level
- When making a key signature, prompt for a certification level. If this
option is not specified, the certification level used is set via
--default-cert-level. See --default-cert-level for
information on the specific levels and how they are used.
--no-ask-cert-level disables this option. This option defaults to
no.
- --default-cert-level n
- The default to use for the check level when signing a key.
0 means you make no particular claim as to how carefully you
verified the key.
1 means you believe the key is owned by the person who claims
to own it but you could not, or did not verify the key at all. This is
useful for a "persona" verification, where you sign the key of
a pseudonymous user.
2 means you did casual verification of the key. For example,
this could mean that you verified the key fingerprint and checked the
user ID on the key against a photo ID.
3 means you did extensive verification of the key. For
example, this could mean that you verified the key fingerprint with the
owner of the key in person, and that you checked, by means of a hard to
forge document with a photo ID (such as a passport) that the name of the
key owner matches the name in the user ID on the key, and finally that
you verified (by exchange of email) that the email address on the key
belongs to the key owner.
Note that the examples given above for levels 2 and 3 are just
that: examples. In the end, it is up to you to decide just what
"casual" and "extensive" mean to you.
This option defaults to 0 (no particular claim).
- --min-cert-level
- When building the trust database, treat any signatures with a
certification level below this as invalid. Defaults to 2, which disregards
level 1 signatures. Note that level 0 "no particular claim"
signatures are always accepted.
- --trusted-key long key ID or fingerprint
- Assume that the specified key (which should be given as fingerprint) is as
trustworthy as one of your own secret keys. This option is useful if you
don't want to keep your secret keys (or one of them) online but still want
to be able to check the validity of a given recipient's or signator's key.
If the given key is not locally available but an LDAP keyserver is
configured the missing key is imported from that server.
- --trust-model {pgp|classic|tofu|tofu+pgp|direct|always|auto}
- Set what trust model GnuPG should follow. The models are:
- pgp
- This is the Web of Trust combined with trust signatures as used in PGP 5.x
and later. This is the default trust model when creating a new trust
database.
- classic
- This is the standard Web of Trust as introduced by PGP 2.
- tofu
-
TOFU stands for Trust On First Use. In this trust model, the
first time a key is seen, it is memorized. If later another key with a
user id with the same email address is seen, both keys are marked as
suspect. In that case, the next time either is used, a warning is
displayed describing the conflict, why it might have occurred (either
the user generated a new key and failed to cross sign the old and new
keys, the key is forgery, or a man-in-the-middle attack is being
attempted), and the user is prompted to manually confirm the validity of
the key in question.
Because a potential attacker is able to control the email
address and thereby circumvent the conflict detection algorithm by using
an email address that is similar in appearance to a trusted email
address, whenever a message is verified, statistics about the number of
messages signed with the key are shown. In this way, a user can easily
identify attacks using fake keys for regular correspondents.
When compared with the Web of Trust, TOFU offers significantly
weaker security guarantees. In particular, TOFU only helps ensure
consistency (that is, that the binding between a key and email address
doesn't change). A major advantage of TOFU is that it requires little
maintenance to use correctly. To use the web of trust properly, you need
to actively sign keys and mark users as trusted introducers. This is a
time-consuming process and anecdotal evidence suggests that even
security-conscious users rarely take the time to do this thoroughly and
instead rely on an ad-hoc TOFU process.
In the TOFU model, policies are associated with bindings
between keys and email addresses (which are extracted from user ids and
normalized). There are five policies, which can be set manually using
the --tofu-policy option. The default policy can be set using the
--tofu-default-policy option.
The TOFU policies are: auto, good,
unknown, bad and ask. The auto policy is
used by default (unless overridden by --tofu-default-policy) and
marks a binding as marginally trusted. The good, unknown
and bad policies mark a binding as fully trusted, as having
unknown trust or as having trust never, respectively. The unknown
policy is useful for just using TOFU to detect conflicts, but to never
assign positive trust to a binding. The final policy, ask prompts
the user to indicate the binding's trust. If batch mode is enabled (or
input is inappropriate in the context), then the user is not prompted
and the undefined trust level is returned.
- tofu+pgp
- This trust model combines TOFU with the Web of Trust. This is done by
computing the trust level for each model and then taking the maximum trust
level where the trust levels are ordered as follows: unknown <
undefined < marginal < fully < ultimate < expired <
never.
By setting --tofu-default-policy=unknown, this model
can be used to implement the web of trust with TOFU's conflict detection
algorithm, but without its assignment of positive trust values, which
some security-conscious users don't like.
- direct
- Key validity is set directly by the user and not calculated via the Web of
Trust. This model is solely based on the key and does not distinguish user
IDs. Note that when changing to another trust model the trust values
assigned to a key are transformed into ownertrust values, which also
indicate how you trust the owner of the key to sign other keys.
- always
- Skip key validation and assume that used keys are always fully valid. You
generally won't use this unless you are using some external validation
scheme. This option also suppresses the "[uncertain]" tag
printed with signature checks when there is no evidence that the user ID
is bound to the key. Note that this trust model still does not allow the
use of expired, revoked, or disabled keys.
- auto
- Select the trust model depending on whatever the internal trust database
says. This is the default model if such a database already exists. Note
that a tofu trust model is not considered here and must be enabled
explicitly.
- --auto-key-locate mechanisms
- --no-auto-key-locate
- GnuPG can automatically locate and retrieve keys as needed using this
option. This happens when encrypting to an email address (in the
"user@example.com" form), and there are no
"user@example.com" keys on the local keyring. This option takes
any number of the mechanisms listed below, in the order they are to be
tried. Instead of listing the mechanisms as comma delimited arguments, the
option may also be given several times to add more mechanism. The option
--no-auto-key-locate or the mechanism "clear" resets the
list. The default is "local,wkd".
- cert
- Locate a key using DNS CERT, as specified in RFC-4398.
- dane
- Locate a key using DANE, as specified in
draft-ietf-dane-openpgpkey-05.txt.
- wkd
- Locate a key using the Web Key Directory protocol.
- ldap
- Using DNS Service Discovery, check the domain in question for any LDAP
keyservers to use. If this fails, attempt to locate the key using the PGP
Universal method of checking ‘ldap://keys.(thedomain)’.
- ntds
- Locate the key using the Active Directory (Windows only). This method also
allows to search by fingerprint using the command
--locate-external-key.
- keyserver
- Locate a key using a keyserver. This method also allows to search by
fingerprint using the command --locate-external-key if any of the
configured keyservers is an LDAP server.
- keyserver-URL
- In addition, a keyserver URL as used in the dirmngr configuration
may be used here to query that particular keyserver. This method also
allows to search by fingerprint using the command
--locate-external-key if the URL specifies an LDAP server.
- local
- Locate the key using the local keyrings. This mechanism allows the user to
select the order a local key lookup is done. Thus using
‘--auto-key-locate local’ is identical to
--no-auto-key-locate.
- nodefault
- This flag disables the standard local key lookup, done before any of the
mechanisms defined by the --auto-key-locate are tried. The position
of this mechanism in the list does not matter. It is not required if
local is also used.
- clear
- Clear all defined mechanisms. This is useful to override mechanisms given
in a config file. Note that a nodefault in mechanisms will
also be cleared unless it is given after the clear.
- --auto-key-import
- --no-auto-key-import
- This is an offline mechanism to get a missing key for signature
verification and for later encryption to this key. If this option is
enabled and a signature includes an embedded key, that key is used to
verify the signature and on verification success the key is imported. The
default is --no-auto-key-import.
On the sender (signing) site the option
--include-key-block needs to be used to put the public part of
the signing key as “Key Block subpacket” into the
signature.
- --auto-key-retrieve
- --no-auto-key-retrieve
- These options enable or disable the automatic retrieving of keys from a
keyserver when verifying signatures made by keys that are not on the local
keyring. The default is --no-auto-key-retrieve.
The order of methods tried to lookup the key is:
1. If the option --auto-key-import is set and the
signatures includes an embedded key, that key is used to verify the
signature and on verification success that key is imported.
2. If a preferred keyserver is specified in the signature and
the option honor-keyserver-url is active (which is not the
default), that keyserver is tried. Note that the creator of the
signature uses the option --sig-keyserver-url to specify the
preferred keyserver for data signatures.
3. If the signature has the Signer's UID set (e.g. using
--sender while creating the signature) a Web Key Directory (WKD)
lookup is done. This is the default configuration but can be disabled by
removing WKD from the auto-key-locate list or by using the option
--disable-signer-uid.
4. If any keyserver is configured and the Issuer Fingerprint
is part of the signature (since GnuPG 2.1.16), the configured keyservers
are tried.
Note that this option makes a "web bug" like
behavior possible. Keyserver or Web Key Directory operators can see
which keys you request, so by sending you a message signed by a brand
new key (which you naturally will not have on your local keyring), the
operator can tell both your IP address and the time when you verified
the signature.
- --keyid-format {none|short|0xshort|long|0xlong}
- Select how to display key IDs. "none" does not show the key ID
at all but shows the fingerprint in a separate line. "short" is
the traditional 8-character key ID. "long" is the more accurate
(but less convenient) 16-character key ID. Add an "0x" to either
to include an "0x" at the beginning of the key ID, as in
0x99242560. Note that this option is ignored if the option
--with-colons is used.
- --keyserver name
- This option is deprecated - please use the --keyserver in
‘dirmngr.conf’ instead.
Use name as your keyserver. This is the server that
--receive-keys, --send-keys, and --search-keys will
communicate with to receive keys from, send keys to, and search for keys
on. The format of the name is a URI:
`scheme:[//]keyservername[:port]' The scheme is the type of keyserver:
"hkp"/"hkps" for the HTTP (or compatible) keyservers
or "ldap"/"ldaps" for the LDAP keyservers. Note that
your particular installation of GnuPG may have other keyserver types
available as well. Keyserver schemes are case-insensitive.
Most keyservers synchronize with each other, so there is
generally no need to send keys to more than one server. The keyserver
hkp://keys.gnupg.net uses round robin DNS to give a different
keyserver each time you use it.
- --keyserver-options {name=value}
- This is a space or comma delimited string that gives options for the
keyserver. Options can be prefixed with a `no-' to give the opposite
meaning. Valid import-options or export-options may be used here as well
to apply to importing (--recv-key) or exporting (--send-key)
a key from a keyserver. While not all options are available for all
keyserver types, some common options are:
- include-revoked
- When searching for a key with --search-keys, include keys that are
marked on the keyserver as revoked. Note that not all keyservers
differentiate between revoked and unrevoked keys, and for such keyservers
this option is meaningless. Note also that most keyservers do not have
cryptographic verification of key revocations, and so turning this option
off may result in skipping keys that are incorrectly marked as revoked.
- include-disabled
- When searching for a key with --search-keys, include keys that are
marked on the keyserver as disabled. Note that this option is not used
with HKP keyservers.
- auto-key-retrieve
- This is an obsolete alias for the option auto-key-retrieve. Please
do not use it; it will be removed in future versions..
- honor-keyserver-url
- When using --refresh-keys, if the key in question has a preferred
keyserver URL, then use that preferred keyserver to refresh the key from.
In addition, if auto-key-retrieve is set, and the signature being verified
has a preferred keyserver URL, then use that preferred keyserver to fetch
the key from. Note that this option introduces a "web bug": The
creator of the key can see when the keys is refreshed. Thus this option is
not enabled by default.
- include-subkeys
- When receiving a key, include subkeys as potential targets. Note that this
option is not used with HKP keyservers, as they do not support retrieving
keys by subkey id.
- timeout
- http-proxy=value
- verbose
- debug
- check-cert
- ca-cert-file
- These options have no more function since GnuPG 2.1. Use the
dirmngr configuration options instead.
The default list of options is: "self-sigs-only,
import-clean, repair-keys, repair-pks-subkey-bug, export-attributes".
However, if the actual used source is an LDAP server
"no-self-sigs-only" is assumed unless "self-sigs-only"
has been explictly configured.
- --completes-needed n
- Number of completely trusted users to introduce a new key signer (defaults
to 1).
- --marginals-needed n
- Number of marginally trusted users to introduce a new key signer (defaults
to 3)
- --tofu-default-policy {auto|good|unknown|bad|ask}
- The default TOFU policy (defaults to auto). For more information
about the meaning of this option, see: [trust-model-tofu].
- --max-cert-depth n
- Maximum depth of a certification chain (default is 5).
- --no-sig-cache
- Do not cache the verification status of key signatures. Caching gives a
much better performance in key listings. However, if you suspect that your
public keyring is not safe against write modifications, you can use this
option to disable the caching. It probably does not make sense to disable
it because all kind of damage can be done if someone else has write access
to your public keyring.
- --auto-check-trustdb
- --no-auto-check-trustdb
- If GnuPG feels that its information about the Web of Trust has to be
updated, it automatically runs the --check-trustdb command
internally. This may be a time consuming process.
--no-auto-check-trustdb disables this option.
- --use-agent
- --no-use-agent
- This is dummy option. gpg2 always requires the agent.
- --gpg-agent-info
- This is dummy option. It has no effect when used with gpg2.
- --agent-program file
- Specify an agent program to be used for secret key operations. The default
value is determined by running gpgconf with the option
--list-dirs. Note that the pipe symbol (|) is used for a
regression test suite hack and may thus not be used in the file name.
- --dirmngr-program file
- Specify a dirmngr program to be used for keyserver access. The default
value is ‘/usr/local/bin/dirmngr’.
- --disable-dirmngr
- Entirely disable the use of the Dirmngr.
- --no-autostart
- Do not start the gpg-agent or the dirmngr if it has not yet been started
and its service is required. This option is mostly useful on machines
where the connection to gpg-agent has been redirected to another machines.
If dirmngr is required on the remote machine, it may be started manually
using gpgconf --launch dirmngr.
- --lock-once
- Lock the databases the first time a lock is requested and do not release
the lock until the process terminates.
- --lock-multiple
- Release the locks every time a lock is no longer needed. Use this to
override a previous --lock-once from a config file.
- --lock-never
- Disable locking entirely. This option should be used only in very special
environments, where it can be assured that only one process is accessing
those files. A bootable floppy with a stand-alone encryption system will
probably use this. Improper usage of this option may lead to data and key
corruption.
- --exit-on-status-write-error
- This option will cause write errors on the status FD to immediately
terminate the process. That should in fact be the default but it never
worked this way and thus we need an option to enable this, so that the
change won't break applications which close their end of a status fd
connected pipe too early. Using this option along with
--enable-progress-filter may be used to cleanly cancel long running
gpg operations.
- --limit-card-insert-tries n
- With n greater than 0 the number of prompts asking to insert a
smartcard gets limited to N-1. Thus with a value of 1 gpg won't at all ask
to insert a card if none has been inserted at startup. This option is
useful in the configuration file in case an application does not know
about the smartcard support and waits ad infinitum for an inserted card.
- --no-random-seed-file
- GnuPG uses a file to store its internal random pool over invocations. This
makes random generation faster; however sometimes write operations are not
desired. This option can be used to achieve that with the cost of slower
random generation.
- --no-greeting
- Suppress the initial copyright message.
- --no-secmem-warning
- Suppress the warning about "using insecure memory".
- --no-permission-warning
- Suppress the warning about unsafe file and home directory
(--homedir) permissions. Note that the permission checks that GnuPG
performs are not intended to be authoritative, but rather they simply warn
about certain common permission problems. Do not assume that the lack of a
warning means that your system is secure.
Note that the warning for unsafe --homedir permissions
cannot be suppressed in the gpg.conf file, as this would allow an
attacker to place an unsafe gpg.conf file in place, and use this file to
suppress warnings about itself. The --homedir permissions warning
may only be suppressed on the command line.
- --require-secmem
- --no-require-secmem
- Refuse to run if GnuPG cannot get secure memory. Defaults to no (i.e. run,
but give a warning).
- --require-cross-certification
- --no-require-cross-certification
- When verifying a signature made from a subkey, ensure that the cross
certification "back signature" on the subkey is present and
valid. This protects against a subtle attack against subkeys that can
sign. Defaults to --require-cross-certification for gpg2.
- --expert
- --no-expert
- Allow the user to do certain nonsensical or "silly" things like
signing an expired or revoked key, or certain potentially incompatible
things like generating unusual key types. This also disables certain
warning messages about potentially incompatible actions. As the name
implies, this option is for experts only. If you don't fully understand
the implications of what it allows you to do, leave this off.
--no-expert disables this option.
- --recipient name
- -r
- Encrypt for user id name. If this option or
--hidden-recipient is not specified, GnuPG asks for the user-id
unless --default-recipient is given.
- --hidden-recipient name
- -R
- Encrypt for user ID name, but hide the key ID of this user's key.
This option helps to hide the receiver of the message and is a limited
countermeasure against traffic analysis. If this option or
--recipient is not specified, GnuPG asks for the user ID unless
--default-recipient is given.
- --recipient-file file
- -f
- This option is similar to --recipient except that it encrypts to a
key stored in the given file. file must be the name of a file
containing exactly one key. gpg2 assumes that the key in this file
is fully valid.
- --hidden-recipient-file file
- -F
- This option is similar to --hidden-recipient except that it
encrypts to a key stored in the given file. file must be the name
of a file containing exactly one key. gpg2 assumes that the key in
this file is fully valid.
- --encrypt-to name
- Same as --recipient but this one is intended for use in the options
file and may be used with your own user-id as an
"encrypt-to-self". These keys are only used when there are other
recipients given either by use of --recipient or by the asked user
id. No trust checking is performed for these user ids and even disabled
keys can be used.
- --hidden-encrypt-to name
- Same as --hidden-recipient but this one is intended for use in the
options file and may be used with your own user-id as a hidden
"encrypt-to-self". These keys are only used when there are other
recipients given either by use of --recipient or by the asked user
id. No trust checking is performed for these user ids and even disabled
keys can be used.
- --no-encrypt-to
- Disable the use of all --encrypt-to and --hidden-encrypt-to
keys.
- --group {name=value}
- Sets up a named group, which is similar to aliases in email programs. Any
time the group name is a recipient (-r or --recipient), it
will be expanded to the values specified. Multiple groups with the same
name are automatically merged into a single group.
The values are key IDs or fingerprints, but any key
description is accepted. Note that a value with spaces in it will be
treated as two different values. Note also there is only one level of
expansion --- you cannot make an group that points to another group.
When used from the command line, it may be necessary to quote the
argument to this option to prevent the shell from treating it as
multiple arguments.
- --ungroup name
- Remove a given entry from the --group list.
- --no-groups
- Remove all entries from the --group list.
- --local-user name
- -u
- Use name as the key to sign with. Note that this option overrides
--default-key.
- --sender mbox
- This option has two purposes. mbox must either be a complete user
ID containing a proper mail address or just a plain mail address. The
option can be given multiple times.
When creating a signature this option tells gpg the signing
key's user id used to make the signature and embeds that user ID into
the created signature (using OpenPGP's ``Signer's User ID'' subpacket).
If the option is given multiple times a suitable user ID is picked.
However, if the signing key was specified directly by using a mail
address (i.e. not by using a fingerprint or key ID) this option is used
and the mail address is embedded in the created signature.
When verifying a signature mbox is used to restrict the
information printed by the TOFU code to matching user IDs. If the option
is used and the signature contains a ``Signer's User ID'' subpacket that
information is is also used to restrict the printed information. Note
that GnuPG considers only the mail address part of a User ID.
If this option or the said subpacket is available the TRUST
lines as printed by option status-fd correspond to the
corresponding User ID; if no User ID is known the TRUST lines are
computed directly on the key and do not give any information about the
User ID. In the latter case it his highly recommended to scripts and
other frontends to evaluate the VALIDSIG line, retrieve the key and
print all User IDs along with their validity (trust) information.
- --try-secret-key name
- For hidden recipients GPG needs to know the keys to use for trial
decryption. The key set with --default-key is always tried first,
but this is often not sufficient. This option allows setting more keys to
be used for trial decryption. Although any valid user-id specification may
be used for name it makes sense to use at least the long keyid to
avoid ambiguities. Note that gpg-agent might pop up a pinentry for a lot
keys to do the trial decryption. If you want to stop all further trial
decryption you may use close-window button instead of the cancel button.
- --try-all-secrets
- Don't look at the key ID as stored in the message but try all secret keys
in turn to find the right decryption key. This option forces the behaviour
as used by anonymous recipients (created by using --throw-keyids or
--hidden-recipient) and might come handy in case where an encrypted
message contains a bogus key ID.
- --skip-hidden-recipients
- --no-skip-hidden-recipients
- During decryption skip all anonymous recipients. This option helps in the
case that people use the hidden recipients feature to hide their own
encrypt-to key from others. If one has many secret keys this may lead to a
major annoyance because all keys are tried in turn to decrypt something
which was not really intended for it. The drawback of this option is that
it is currently not possible to decrypt a message which includes real
anonymous recipients.
- --armor
- -a
- Create ASCII armored output. The default is to create the binary OpenPGP
format.
- --no-armor
- Assume the input data is not in ASCII armored format.
- --output file
- -o file
- Write output to file. To write to stdout use - as the
filename.
- --max-output n
- This option sets a limit on the number of bytes that will be generated
when processing a file. Since OpenPGP supports various levels of
compression, it is possible that the plaintext of a given message may be
significantly larger than the original OpenPGP message. While GnuPG works
properly with such messages, there is often a desire to set a maximum file
size that will be generated before processing is forced to stop by the OS
limits. Defaults to 0, which means "no limit".
- --chunk-size n
- The AEAD encryption mode encrypts the data in chunks so that a receiving
side can check for transmission errors or tampering at the end of each
chunk and does not need to delay this until all data has been received.
The used chunk size is 2^n byte. The lowest allowed value for
n is 6 (64 byte) and the largest is the default of 22 which creates
chunks not larger than 4 MiB.
- --input-size-hint n
- This option can be used to tell GPG the size of the input data in bytes.
n must be a positive base-10 number. This option is only useful if
the input is not taken from a file. GPG may use this hint to optimize its
buffer allocation strategy. It is also used by the --status-fd line
``PROGRESS'' to provide a value for ``total'' if that is not available by
other means.
- --key-origin string[,url]
- gpg can track the origin of a key. Certain origins are implicitly known
(e.g. keyserver, web key directory) and set. For a standard import the
origin of the keys imported can be set with this option. To list the
possible values use "help" for string. Some origins can
store an optional url argument. That URL can appended to
string after a comma.
- --import-options parameters
- This is a space or comma delimited string that gives options for importing
keys. Options can be prepended with a `no-' to give the opposite meaning.
The options are:
- import-local-sigs
- Allow importing key signatures marked as "local". This is not
generally useful unless a shared keyring scheme is being used. Defaults to
no.
- keep-ownertrust
- Normally possible still existing ownertrust values of a key are cleared if
a key is imported. This is in general desirable so that a formerly deleted
key does not automatically gain an ownertrust values merely due to import.
On the other hand it is sometimes necessary to re-import a trusted set of
keys again but keeping already assigned ownertrust values. This can be
achieved by using this option.
- repair-pks-subkey-bug
- During import, attempt to repair the damage caused by the PKS keyserver
bug (pre version 0.9.6) that mangles keys with multiple subkeys. Note that
this cannot completely repair the damaged key as some crucial data is
removed by the keyserver, but it does at least give you back one subkey.
Defaults to no for regular --import and to yes for keyserver
--receive-keys.
- import-show
- show-only
- Show a listing of the key as imported right before it is stored. This can
be combined with the option --dry-run to only look at keys; the
option show-only is a shortcut for this combination. The command
--show-keys is another shortcut for this. Note that suffixes like
'#' for "sec" and "sbb" lines may or may not be
printed.
- import-export
- Run the entire import code but instead of storing the key to the local
keyring write it to the output. The export option export-dane
affect the output. This option can for example be used to remove all
invalid parts from a key without the need to store it.
- merge-only
- During import, allow key updates to existing keys, but do not allow any
new keys to be imported. Defaults to no.
- import-clean
- After import, compact (remove all signatures except the self-signature)
any user IDs from the new key that are not usable. Then, remove any
signatures from the new key that are not usable. This includes signatures
that were issued by keys that are not present on the keyring. This option
is the same as running the --edit-key command "clean"
after import. Defaults to no.
- self-sigs-only
- Accept only self-signatures while importing a key. All other key
signatures are skipped at an early import stage. This option can be used
with keyserver-options to mitigate attempts to flood a key with
bogus signatures from a keyserver. The drawback is that all other valid
key signatures, as required by the Web of Trust are also not imported.
Note that when using this option along with import-clean it suppresses the
final clean step after merging the imported key into the existing key.
- repair-keys
- After import, fix various problems with the keys. For example, this
reorders signatures, and strips duplicate signatures. Defaults to yes.
- bulk-import
- When used the keyboxd (option use-keyboxd in
‘common.conf’) does the import within a single
transaction.
- import-minimal
- Import the smallest key possible. This removes all signatures except the
most recent self-signature on each user ID. This option is the same as
running the --edit-key command "minimize" after import.
Defaults to no.
- restore
- import-restore
- Import in key restore mode. This imports all data which is usually skipped
during import; including all GnuPG specific data. All other contradicting
options are overridden.
- --import-filter {name=expr}
- --export-filter {name=expr}
- These options define an import/export filter which are applied to the
imported/exported keyblock right before it will be stored/written.
name defines the type of filter to use, expr the expression
to evaluate. The option can be used several times which then appends more
expression to the same name.
The available filter types are:
- keep-uid
- This filter will keep a user id packet and its dependent packets in the
keyblock if the expression evaluates to true.
- drop-subkey
- This filter drops the selected subkeys. Currently only implemented for
--export-filter.
- drop-sig
- This filter drops the selected key signatures on user ids. Self-signatures
are not considered. Currently only implemented for --import-filter.
For the syntax of the expression see the chapter "FILTER
EXPRESSIONS". The property names for the expressions depend on the
actual filter type and are indicated in the following table.
The available properties are:
- uid
- A string with the user id. (keep-uid)
- mbox
- The addr-spec part of a user id with mailbox or the empty string.
(keep-uid)
- key_algo
- A number with the public key algorithm of a key or subkey packet.
(drop-subkey)
- key_created
- key_created_d
- The first is the timestamp a public key or subkey packet was created. The
second is the same but given as an ISO string, e.g.
"2016-08-17". (drop-subkey)
- fpr
- The hexified fingerprint of the current subkey or primary key.
(drop-subkey)
- primary
- Boolean indicating whether the user id is the primary one. (keep-uid)
- expired
- Boolean indicating whether a user id (keep-uid), a key (drop-subkey), or a
signature (drop-sig) expired.
- revoked
- Boolean indicating whether a user id (keep-uid) or a key (drop-subkey) has
been revoked.
- disabled
- Boolean indicating whether a primary key is disabled. (not used)
- secret
- Boolean indicating whether a key or subkey is a secret one. (drop-subkey)
- usage
- A string indicating the usage flags for the subkey, from the sequence
``ecsa?''. For example, a subkey capable of just signing and
authentication would be an exact match for ``sa''. (drop-subkey)
- sig_created
- sig_created_d
- The first is the timestamp a signature packet was created. The second is
the same but given as an ISO date string, e.g. "2016-08-17".
(drop-sig)
- sig_algo
- A number with the public key algorithm of a signature packet. (drop-sig)
- sig_digest_algo
- A number with the digest algorithm of a signature packet. (drop-sig)
- --export-options parameters
- This is a space or comma delimited string that gives options for exporting
keys. Options can be prepended with a `no-' to give the opposite meaning.
The options are:
- export-local-sigs
- Allow exporting key signatures marked as "local". This is not
generally useful unless a shared keyring scheme is being used. Defaults to
no.
- export-attributes
- Include attribute user IDs (photo IDs) while exporting. Not including
attribute user IDs is useful to export keys that are going to be used by
an OpenPGP program that does not accept attribute user IDs. Defaults to
yes.
- export-sensitive-revkeys
- Include designated revoker information that was marked as
"sensitive". Defaults to no.
- backup
- export-backup
- Export for use as a backup. The exported data includes all data which is
needed to restore the key or keys later with GnuPG. The format is
basically the OpenPGP format but enhanced with GnuPG specific data. All
other contradicting options are overridden.
- export-clean
- Compact (remove all signatures from) user IDs on the key being exported if
the user IDs are not usable. Also, do not export any signatures that are
not usable. This includes signatures that were issued by keys that are not
present on the keyring. This option is the same as running the
--edit-key command "clean" before export except that the
local copy of the key is not modified. Defaults to no.
- export-minimal
- Export the smallest key possible. This removes all signatures except the
most recent self-signature on each user ID. This option is the same as
running the --edit-key command "minimize" before export
except that the local copy of the key is not modified. Defaults to no.
- export-dane
- Instead of outputting the key material output OpenPGP DANE records
suitable to put into DNS zone files. An ORIGIN line is printed before each
record to allow diverting the records to the corresponding zone file.
- --with-colons
- Print key listings delimited by colons. Note that the output will be
encoded in UTF-8 regardless of any --display-charset setting. This
format is useful when GnuPG is called from scripts and other programs as
it is easily machine parsed. The details of this format are documented in
the file ‘doc/DETAILS’, which is included in the
GnuPG source distribution.
- --fixed-list-mode
- Do not merge primary user ID and primary key in --with-colon
listing mode and print all timestamps as seconds since 1970-01-01. Since
GnuPG 2.0.10, this mode is always used and thus this option is obsolete;
it does not harm to use it though.
- --legacy-list-mode
- Revert to the pre-2.1 public key list mode. This only affects the human
readable output and not the machine interface (i.e. --with-colons).
Note that the legacy format does not convey suitable information for
elliptic curves.
- --with-fingerprint
- Same as the command --fingerprint but changes only the format of
the output and may be used together with another command.
- --with-subkey-fingerprint
- If a fingerprint is printed for the primary key, this option forces
printing of the fingerprint for all subkeys. This could also be achieved
by using the --with-fingerprint twice but by using this option
along with keyid-format "none" a compact fingerprint is printed.
- --with-icao-spelling
- Print the ICAO spelling of the fingerprint in addition to the hex digits.
- --with-keygrip
- Include the keygrip in the key listings. In --with-colons mode this
is implicitly enable for secret keys.
- --with-key-origin
- Include the locally held information on the origin and last update of a
key in a key listing. In --with-colons mode this is always printed.
This data is currently experimental and shall not be considered part of
the stable API.
- --with-wkd-hash
- Print a Web Key Directory identifier along with each user ID in key
listings. This is an experimental feature and semantics may change.
- --with-secret
- Include info about the presence of a secret key in public key listings
done with --with-colons.
- -t, --textmode
- --no-textmode
- Treat input files as text and store them in the OpenPGP canonical text
form with standard "CRLF" line endings. This also sets the
necessary flags to inform the recipient that the encrypted or signed data
is text and may need its line endings converted back to whatever the local
system uses. This option is useful when communicating between two
platforms that have different line ending conventions (UNIX-like to Mac,
Mac to Windows, etc). --no-textmode disables this option, and is
the default.
- --force-v3-sigs
- --no-force-v3-sigs
- --force-v4-certs
- --no-force-v4-certs
- These options are obsolete and have no effect since GnuPG 2.1.
- --force-aead
- Force the use of AEAD encryption over MDC encryption. AEAD is a modern and
faster way to do authenticated encryption than the old MDC method. See
also options --aead-algo and --chunk-size.
- --force-mdc
- --disable-mdc
- These options are obsolete and have no effect since GnuPG 2.2.8. The MDC
is always used unless the keys indicate that an AEAD algorithm can be used
in which case AEAD is used. But note: If the creation of a legacy non-MDC
message is exceptionally required, the option --rfc2440 allows for
this.
- --disable-signer-uid
- By default the user ID of the signing key is embedded in the data
signature. As of now this is only done if the signing key has been
specified with local-user using a mail address, or with
sender. This information can be helpful for verifier to locate the
key; see option --auto-key-retrieve.
- --include-key-block
- --no-include-key-block
- This option is used to embed the actual signing key into a data signature.
The embedded key is stripped down to a single user id and includes only
the signing subkey used to create the signature as well as as valid
encryption subkeys. All other info is removed from the key to keep it and
thus the signature small. This option is the OpenPGP counterpart to the
gpgsm option --include-certs and allows the recipient of a
signed message to reply encrypted to the sender without using any online
directories to lookup the key. The default is
--no-include-key-block. See also the option
--auto-key-import.
- --personal-cipher-preferences string
- Set the list of personal cipher preferences to string. Use gpg2
--version to get a list of available algorithms, and use none
to set no preference at all. This allows the user to safely override the
algorithm chosen by the recipient key preferences, as GPG will only select
an algorithm that is usable by all recipients. The most highly ranked
cipher in this list is also used for the --symmetric encryption
command.
- --personal-aead-preferences string
- Set the list of personal AEAD preferences to string. Use gpg2
--version to get a list of available algorithms, and use none
to set no preference at all. This allows the user to safely override the
algorithm chosen by the recipient key preferences, as GPG will only select
an algorithm that is usable by all recipients. The most highly ranked
cipher in this list is also used for the --symmetric encryption
command.
- --personal-digest-preferences string
- Set the list of personal digest preferences to string. Use gpg2
--version to get a list of available algorithms, and use none
to set no preference at all. This allows the user to safely override the
algorithm chosen by the recipient key preferences, as GPG will only select
an algorithm that is usable by all recipients. The most highly ranked
digest algorithm in this list is also used when signing without encryption
(e.g. --clear-sign or --sign).
- --personal-compress-preferences string
- Set the list of personal compression preferences to string. Use
gpg2 --version to get a list of available algorithms, and use
none to set no preference at all. This allows the user to safely
override the algorithm chosen by the recipient key preferences, as GPG
will only select an algorithm that is usable by all recipients. The most
highly ranked compression algorithm in this list is also used when there
are no recipient keys to consider (e.g. --symmetric).
- --s2k-cipher-algo name
- Use name as the cipher algorithm for symmetric encryption with a
passphrase if --personal-cipher-preferences and
--cipher-algo are not given. The default is AES-128.
- --s2k-digest-algo name
- Use name as the digest algorithm used to mangle the passphrases for
symmetric encryption. The default is SHA-1.
- --s2k-mode n
- Selects how passphrases for symmetric encryption are mangled. If n
is 0 a plain passphrase (which is in general not recommended) will be
used, a 1 adds a salt (which should not be used) to the passphrase and a 3
(the default) iterates the whole process a number of times (see
--s2k-count).
- --s2k-count n
- Specify how many times the passphrases mangling for symmetric encryption
is repeated. This value may range between 1024 and 65011712 inclusive. The
default is inquired from gpg-agent. Note that not all values in the
1024-65011712 range are legal and if an illegal value is selected, GnuPG
will round up to the nearest legal value. This option is only meaningful
if --s2k-mode is set to the default of 3.
These options control what GnuPG is compliant to. Only one of
these options may be active at a time. Note that the default setting of this
is nearly always the correct one. See the INTEROPERABILITY WITH OTHER
OPENPGP PROGRAMS section below before using one of these options.
- --gnupg
- Use standard GnuPG behavior. This is essentially OpenPGP behavior (see
--openpgp), but with extension from the proposed update to OpenPGP
and with some additional workarounds for common compatibility problems in
different versions of PGP. This is the default option, so it is not
generally needed, but it may be useful to override a different compliance
option in the gpg.conf file.
- --openpgp
- Reset all packet, cipher and digest options to strict OpenPGP behavior.
This option implies --allow-old-cipher-algos. Use this option to
reset all previous options like --s2k-*, --cipher-algo,
--digest-algo and --compress-algo to OpenPGP compliant
values. All PGP workarounds are disabled.
- --rfc4880
- Reset all packet, cipher and digest options to strict RFC-4880 behavior.
This option implies --allow-old-cipher-algos. Note that this is
currently the same thing as --openpgp.
- --rfc4880bis
- Reset all packet, cipher and digest options to strict according to the
proposed updates of RFC-4880.
- --rfc2440
- Reset all packet, cipher and digest options to strict RFC-2440 behavior.
Note that by using this option encryption packets are created in a legacy
mode without MDC protection. This is dangerous and should thus only be
used for experiments. This option implies --allow-old-cipher-algos.
See also option --ignore-mdc-error.
- --pgp6
- This option is obsolete; it is handled as an alias for --pgp7
- --pgp7
- Set up all options to be as PGP 7 compliant as possible. This allowed the
ciphers IDEA, 3DES, CAST5,AES128, AES192, AES256, and TWOFISH., the hashes
MD5, SHA1 and RIPEMD160, and the compression algorithms none and ZIP. This
option implies --escape-from-lines and disables
--throw-keyids,
- --pgp8
- Set up all options to be as PGP 8 compliant as possible. PGP 8 is a lot
closer to the OpenPGP standard than previous versions of PGP, so all this
does is disable --throw-keyids and set --escape-from-lines.
All algorithms are allowed except for the SHA224, SHA384, and SHA512
digests.
- --compliance string
- This option can be used instead of one of the options above. Valid values
for string are the above option names (without the double dash) and
possibly others as shown when using "help" for value.
- -n
- --dry-run
- Don't make any changes (this is not completely implemented).
- --list-only
- Changes the behaviour of some commands. This is like --dry-run but
different in some cases. The semantic of this option may be extended in
the future. Currently it only skips the actual decryption pass and
therefore enables a fast listing of the encryption keys.
- -i
- --interactive
- Prompt before overwriting any files.
- --debug-level level
- Select the debug level for investigating problems. level may be a
numeric value or by a keyword:
- none
- No debugging at all. A value of less than 1 may be used instead of the
keyword.
- basic
- Some basic debug messages. A value between 1 and 2 may be used instead of
the keyword.
- advanced
- More verbose debug messages. A value between 3 and 5 may be used instead
of the keyword.
- expert
- Even more detailed messages. A value between 6 and 8 may be used instead
of the keyword.
- guru
- All of the debug messages you can get. A value greater than 8 may be used
instead of the keyword. The creation of hash tracing files is only enabled
if the keyword is used.
How these messages are mapped to the actual debugging flags is not
specified and may change with newer releases of this program. They are
however carefully selected to best aid in debugging.
- --debug flags
- Set debug flags. All flags are or-ed and flags may be given in C
syntax (e.g. 0x0042) or as a comma separated list of flag names. To get a
list of all supported flags the single word "help" can be used.
This option is only useful for debugging and the behavior may change at
any time without notice.
- --debug-all
- Set all useful debugging flags.
- --debug-iolbf
- Set stdout into line buffered mode. This option is only honored when given
on the command line.
- --debug-set-iobuf-size n
- Change the buffer size of the IOBUFs to n kilobyte. Using 0 prints
the current size. Note well: This is a maintainer only option and may thus
be changed or removed at any time without notice.
- --debug-allow-large-chunks
- To facilitate software tests and experiments this option allows to specify
a limit of up to 4 EiB (--chunk-size 62).
- --faked-system-time epoch
- This option is only useful for testing; it sets the system time back or
forth to epoch which is the number of seconds elapsed since the
year 1970. Alternatively epoch may be given as a full ISO time
string (e.g. "20070924T154812").
If you suffix epoch with an exclamation mark (!), the
system time will appear to be frozen at the specified time.
- --full-timestrings
- Change the format of printed creation and expiration times from just the
date to the date and time. This is in general not useful and the same
information is anyway available in --with-colons mode. These longer
strings are also not well aligned with other printed data.
- --enable-progress-filter
- Enable certain PROGRESS status outputs. This option allows frontends to
display a progress indicator while gpg is processing larger files. There
is a slight performance overhead using it.
- --status-fd n
- Write special status strings to the file descriptor n. See the file
DETAILS in the documentation for a listing of them.
- --status-file file
- Same as --status-fd, except the status data is written to file
file.
- --logger-fd n
- Write log output to file descriptor n and not to STDERR.
- --log-file file
- --logger-file file
- Same as --logger-fd, except the logger data is written to file
file. Use ‘socket://’ to log to s socket.
- --attribute-fd n
- Write attribute subpackets to the file descriptor n. This is most
useful for use with --status-fd, since the status messages are
needed to separate out the various subpackets from the stream delivered to
the file descriptor.
- --attribute-file file
- Same as --attribute-fd, except the attribute data is written to
file file.
- --comment string
- --no-comments
- Use string as a comment string in cleartext signatures and ASCII
armored messages or keys (see --armor). The default behavior is not
to use a comment string. --comment may be repeated multiple times
to get multiple comment strings. --no-comments removes all
comments. It is a good idea to keep the length of a single comment below
60 characters to avoid problems with mail programs wrapping such lines.
Note that comment lines, like all other header lines, are not protected by
the signature.
- --emit-version
- --no-emit-version
- Force inclusion of the version string in ASCII armored output. If given
once only the name of the program and the major number is emitted, given
twice the minor is also emitted, given thrice the micro is added, and
given four times an operating system identification is also emitted.
--no-emit-version (default) disables the version line.
- --sig-notation {name=value}
- --cert-notation {name=value}
- -N, --set-notation {name=value}
- Put the name value pair into the signature as notation data. name
must consist only of printable characters or spaces, and must contain a
'@' character in the form keyname@domain.example.com (substituting the
appropriate keyname and domain name, of course). This is to help prevent
pollution of the IETF reserved notation namespace. The --expert
flag overrides the '@' check. value may be any printable string; it
will be encoded in UTF-8, so you should check that your
--display-charset is set correctly. If you prefix name with
an exclamation mark (!), the notation data will be flagged as critical
(rfc4880:5.2.3.16). --sig-notation sets a notation for data
signatures. --cert-notation sets a notation for key signatures
(certifications). --set-notation sets both.
There are special codes that may be used in notation names.
"%k" will be expanded into the key ID of the key being signed,
"%K" into the long key ID of the key being signed,
"%f" into the fingerprint of the key being signed,
"%s" into the key ID of the key making the signature,
"%S" into the long key ID of the key making the signature,
"%g" into the fingerprint of the key making the signature
(which might be a subkey), "%p" into the fingerprint of the
primary key of the key making the signature, "%c" into the
signature count from the OpenPGP smartcard, and "%%" results
in a single "%". %k, %K, and %f are only meaningful when
making a key signature (certification), and %c is only meaningful when
using the OpenPGP smartcard.
- --known-notation name
- Adds name to a list of known critical signature notations. The
effect of this is that gpg will not mark a signature with a critical
signature notation of that name as bad. Note that gpg already knows by
default about a few critical signatures notation names.
- --sig-policy-url string
- --cert-policy-url string
- --set-policy-url string
- Use string as a Policy URL for signatures (rfc4880:5.2.3.20). If
you prefix it with an exclamation mark (!), the policy URL packet will be
flagged as critical. --sig-policy-url sets a policy url for data
signatures. --cert-policy-url sets a policy url for key signatures
(certifications). --set-policy-url sets both.
The same %-expandos used for notation data are available here
as well.
- --sig-keyserver-url string
- Use string as a preferred keyserver URL for data signatures. If you
prefix it with an exclamation mark (!), the keyserver URL packet will be
flagged as critical.
The same %-expandos used for notation data are available here
as well.
- --set-filename string
- Use string as the filename which is stored inside messages. This
overrides the default, which is to use the actual filename of the file
being encrypted. Using the empty string for string effectively
removes the filename from the output.
- --for-your-eyes-only
- --no-for-your-eyes-only
- Set the `for your eyes only' flag in the message. This causes GnuPG to
refuse to save the file unless the --output option is given, and
PGP to use a "secure viewer" with a claimed Tempest-resistant
font to display the message. This option overrides --set-filename.
--no-for-your-eyes-only disables this option.
- --use-embedded-filename
- --no-use-embedded-filename
- Try to create a file with a name as embedded in the data. This can be a
dangerous option as it enables overwriting files. Defaults to no. Note
that the option --output overrides this option.
- --cipher-algo name
- Use name as cipher algorithm. Running the program with the command
--version yields a list of supported algorithms. If this is not
used the cipher algorithm is selected from the preferences stored with the
key. In general, you do not want to use this option as it allows you to
violate the OpenPGP standard. The option
--personal-cipher-preferences is the safe way to accomplish the
same thing.
- --aead-algo name
- Specify that the AEAD algorithm name is to be used. This is useful
for symmetric encryption where no key preference are available to select
the AEAD algorithm. Running gpg2 with option --version shows
the available AEAD algorithms. In general, you do not want to use this
option as it allows you to violate the OpenPGP standard. The option
--personal-aead-preferences is the safe way to accomplish the same
thing.
- --digest-algo name
- Use name as the message digest algorithm. Running the program with
the command --version yields a list of supported algorithms. In
general, you do not want to use this option as it allows you to violate
the OpenPGP standard. The option --personal-digest-preferences is
the safe way to accomplish the same thing.
- --compress-algo name
- Use compression algorithm name. "zlib" is RFC-1950 ZLIB
compression. "zip" is RFC-1951 ZIP compression which is used by
PGP. "bzip2" is a more modern compression scheme that can
compress some things better than zip or zlib, but at the cost of more
memory used during compression and decompression. "uncompressed"
or "none" disables compression. If this option is not used, the
default behavior is to examine the recipient key preferences to see which
algorithms the recipient supports. If all else fails, ZIP is used for
maximum compatibility.
ZLIB may give better compression results than ZIP, as the
compression window size is not limited to 8k. BZIP2 may give even better
compression results than that, but will use a significantly larger
amount of memory while compressing and decompressing. This may be
significant in low memory situations. Note, however, that PGP (all
versions) only supports ZIP compression. Using any algorithm other than
ZIP or "none" will make the message unreadable with PGP. In
general, you do not want to use this option as it allows you to violate
the OpenPGP standard. The option --personal-compress-preferences
is the safe way to accomplish the same thing.
- --cert-digest-algo name
- Use name as the message digest algorithm used when signing a key.
Running the program with the command --version yields a list of
supported algorithms. Be aware that if you choose an algorithm that GnuPG
supports but other OpenPGP implementations do not, then some users will
not be able to use the key signatures you make, or quite possibly your
entire key. Note also that a public key algorithm must be compatible with
the specified digest algorithm; thus selecting an arbitrary digest
algorithm may result in error messages from lower crypto layers or lead to
security flaws.
- --disable-cipher-algo name
- Never allow the use of name as cipher algorithm. The given name
will not be checked so that a later loaded algorithm will still get
disabled.
- --disable-pubkey-algo name
- Never allow the use of name as public key algorithm. The given name
will not be checked so that a later loaded algorithm will still get
disabled.
- --throw-keyids
- --no-throw-keyids
- Do not put the recipient key IDs into encrypted messages. This helps to
hide the receivers of the message and is a limited countermeasure against
traffic analysis. ([Using a little social engineering anyone who is able
to decrypt the message can check whether one of the other recipients is
the one he suspects.]) On the receiving side, it may slow down the
decryption process because all available secret keys must be tried.
--no-throw-keyids disables this option. This option is essentially
the same as using --hidden-recipient for all recipients.
- --not-dash-escaped
- This option changes the behavior of cleartext signatures so that they can
be used for patch files. You should not send such an armored file via
email because all spaces and line endings are hashed too. You can not use
this option for data which has 5 dashes at the beginning of a line, patch
files don't have this. A special armor header line tells GnuPG about this
cleartext signature option.
- --escape-from-lines
- --no-escape-from-lines
- Because some mailers change lines starting with "From " to
">From " it is good to handle such lines in a special way
when creating cleartext signatures to prevent the mail system from
breaking the signature. Note that all other PGP versions do it this way
too. Enabled by default. --no-escape-from-lines disables this
option.
- --passphrase-repeat n
- Specify how many times gpg2 will request a new passphrase be
repeated. This is useful for helping memorize a passphrase. Defaults to 1
repetition; can be set to 0 to disable any passphrase repetition. Note
that a n greater than 1 will pop up the pinentry window n+1
times even if a modern pinentry with two entry fields is used.
- --passphrase-fd n
- Read the passphrase from file descriptor n. Only the first line
will be read from file descriptor n. If you use 0 for n, the
passphrase will be read from STDIN. This can only be used if only one
passphrase is supplied.
Note that since Version 2.0 this passphrase is only used if
the option --batch has also been given. Since Version 2.1 the
--pinentry-mode also needs to be set to loopback.
- --passphrase-file file
- Read the passphrase from file file. Only the first line will be
read from file file. This can only be used if only one passphrase
is supplied. Obviously, a passphrase stored in a file is of questionable
security if other users can read this file. Don't use this option if you
can avoid it.
Note that since Version 2.0 this passphrase is only used if
the option --batch has also been given. Since Version 2.1 the
--pinentry-mode also needs to be set to loopback.
- --passphrase string
- Use string as the passphrase. This can only be used if only one
passphrase is supplied. Obviously, this is of very questionable security
on a multi-user system. Don't use this option if you can avoid it.
Note that since Version 2.0 this passphrase is only used if
the option --batch has also been given. Since Version 2.1 the
--pinentry-mode also needs to be set to loopback.
- --pinentry-mode mode
- Set the pinentry mode to mode. Allowed values for mode
are:
- default
- Use the default of the agent, which is ask.
- ask
- Force the use of the Pinentry.
- cancel
- Emulate use of Pinentry's cancel button.
- error
- Return a Pinentry error (``No Pinentry'').
- loopback
- Redirect Pinentry queries to the caller. Note that in contrast to Pinentry
the user is not prompted again if he enters a bad password.
- --no-symkey-cache
- Disable the passphrase cache used for symmetrical en- and decryption. This
cache is based on the message specific salt value (cf. --s2k-mode).
- --request-origin origin
- Tell gpg to assume that the operation ultimately originated at
origin. Depending on the origin certain restrictions are applied
and the Pinentry may include an extra note on the origin. Supported values
for origin are: local which is the default, remote to
indicate a remote origin or browser for an operation requested by a
web browser.
- --command-fd n
- This is a replacement for the deprecated shared-memory IPC mode. If this
option is enabled, user input on questions is not expected from the TTY
but from the given file descriptor. It should be used together with
--status-fd. See the file doc/DETAILS in the source distribution
for details on how to use it.
- --command-file file
- Same as --command-fd, except the commands are read out of file
file
- --allow-non-selfsigned-uid
- --no-allow-non-selfsigned-uid
- Allow the import and use of keys with user IDs which are not self-signed.
This is not recommended, as a non self-signed user ID is trivial to forge.
--no-allow-non-selfsigned-uid disables.
- --allow-freeform-uid
- Disable all checks on the form of the user ID while generating a new one.
This option should only be used in very special environments as it does
not ensure the de-facto standard format of user IDs.
- --ignore-time-conflict
- GnuPG normally checks that the timestamps associated with keys and
signatures have plausible values. However, sometimes a signature seems to
be older than the key due to clock problems. This option makes these
checks just a warning. See also --ignore-valid-from for timestamp
issues on subkeys.
- --ignore-valid-from
- GnuPG normally does not select and use subkeys created in the future. This
option allows the use of such keys and thus exhibits the pre-1.0.7
behaviour. You should not use this option unless there is some clock
problem. See also --ignore-time-conflict for timestamp issues with
signatures.
- --ignore-crc-error
- The ASCII armor used by OpenPGP is protected by a CRC checksum against
transmission errors. Occasionally the CRC gets mangled somewhere on the
transmission channel but the actual content (which is protected by the
OpenPGP protocol anyway) is still okay. This option allows GnuPG to ignore
CRC errors.
- --ignore-mdc-error
- This option changes a MDC integrity protection failure into a warning. It
is required to decrypt old messages which did not use an MDC. It may also
be useful if a message is partially garbled, but it is necessary to get as
much data as possible out of that garbled message. Be aware that a missing
or failed MDC can be an indication of an attack. Use with great caution;
see also option --rfc2440.
- --allow-old-cipher-algos
- Old cipher algorithms like 3DES, IDEA, or CAST5 encrypt data using blocks
of 64 bits; modern algorithms use blocks of 128 bit instead. To avoid
certain attack on these old algorithms it is suggested not to encrypt more
than 150 MiByte using the same key. For this reason gpg does not allow the
use of 64 bit block size algorithms for encryption unless this option is
specified.
- --allow-weak-digest-algos
- Signatures made with known-weak digest algorithms are normally rejected
with an ``invalid digest algorithm'' message. This option allows the
verification of signatures made with such weak algorithms. MD5 is the only
digest algorithm considered weak by default. See also --weak-digest
to reject other digest algorithms.
- --weak-digest name
- Treat the specified digest algorithm as weak. Signatures made over weak
digests algorithms are normally rejected. This option can be supplied
multiple times if multiple algorithms should be considered weak. See also
--allow-weak-digest-algos to disable rejection of weak digests. MD5
is always considered weak, and does not need to be listed explicitly.
- --allow-weak-key-signatures
- To avoid a minor risk of collision attacks on third-party key signatures
made using SHA-1, those key signatures are considered invalid. This
options allows to override this restriction.
- --no-default-keyring
- Do not add the default keyring to the list of keyrings. Note that GnuPG
needs for almost all operations a keyring. Thus if you use this option and
do not provide alternate keyrings via --keyring, then GnuPG will
still use the default keyring.
Note that if the option use-keyboxd is enabled in
‘common.conf’, no keyrings are used at all and keys
are all maintained by the keyboxd process in its own database.
- --no-keyring
- Do not use any keyring at all. This overrides the default and all options
which specify keyrings.
- --skip-verify
- Skip the signature verification step. This may be used to make the
decryption faster if the signature verification is not needed.
- --with-key-data
- Print key listings delimited by colons (like --with-colons) and
print the public key data.
- --list-signatures
- --list-sigs
- Same as --list-keys, but the signatures are listed too. This
command has the same effect as using --list-keys with
--with-sig-list. Note that in contrast to --check-signatures
the key signatures are not verified. This command can be used to create a
list of signing keys missing in the local keyring; for example:
gpg --list-sigs --with-colons USERID | \
awk -F: '$1=="sig" && $2=="?" {if($13){print $13}else{print $5}}'
- --fast-list-mode
- Changes the output of the list commands to work faster; this is achieved
by leaving some parts empty. Some applications don't need the user ID and
the trust information given in the listings. By using this options they
can get a faster listing. The exact behaviour of this option may change in
future versions. If you are missing some information, don't use this
option.
- --no-literal
- This is not for normal use. Use the source to see for what it might be
useful.
- --set-filesize
- This is not for normal use. Use the source to see for what it might be
useful.
- --show-session-key
- Display the session key used for one message. See
--override-session-key for the counterpart of this option.
We think that Key Escrow is a Bad Thing; however the user
should have the freedom to decide whether to go to prison or to reveal
the content of one specific message without compromising all messages
ever encrypted for one secret key.
You can also use this option if you receive an encrypted
message which is abusive or offensive, to prove to the administrators of
the messaging system that the ciphertext transmitted corresponds to an
inappropriate plaintext so they can take action against the offending
user.
- --override-session-key string
- --override-session-key-fd fd
- Don't use the public key but the session key string respective the
session key taken from the first line read from file descriptor fd.
The format of this string is the same as the one printed by
--show-session-key. This option is normally not used but comes
handy in case someone forces you to reveal the content of an encrypted
message; using this option you can do this without handing out the secret
key. Note that using --override-session-key may reveal the session
key to all local users via the global process table. Often it is useful to
combine this option with --no-keyring.
- --ask-sig-expire
- --no-ask-sig-expire
- When making a data signature, prompt for an expiration time. If this
option is not specified, the expiration time set via
--default-sig-expire is used. --no-ask-sig-expire disables
this option.
- --default-sig-expire
- The default expiration time to use for signature expiration. Valid values
are "0" for no expiration, a number followed by the letter d
(for days), w (for weeks), m (for months), or y (for years) (for example
"2m" for two months, or "5y" for five years), or an
absolute date in the form YYYY-MM-DD. Defaults to "0".
- --ask-cert-expire
- --no-ask-cert-expire
- When making a key signature, prompt for an expiration time. If this option
is not specified, the expiration time set via --default-cert-expire
is used. --no-ask-cert-expire disables this option.
- --default-cert-expire
- The default expiration time to use for key signature expiration. Valid
values are "0" for no expiration, a number followed by the
letter d (for days), w (for weeks), m (for months), or y (for years) (for
example "2m" for two months, or "5y" for five years),
or an absolute date in the form YYYY-MM-DD. Defaults to "0".
- --default-new-key-algo string
- This option can be used to change the default algorithms for key
generation. The string is similar to the arguments required for the
command --quick-add-key but slightly different. For example the
current default of "rsa2048/cert,sign+rsa2048/encr" (or
"rsa3072") can be changed to the value of what we
currently call future default, which is
"ed25519/cert,sign+cv25519/encr". You need to consult the
source code to learn the details. Note that the advanced key generation
commands can always be used to specify a key algorithm directly.
- --no-auto-trust-new-key
- When creating a new key the ownertrust of the new key is set to ultimate.
This option disables this and the user needs to manually assign an
ownertrust value.
- --force-sign-key
- This option modifies the behaviour of the commands
--quick-sign-key, --quick-lsign-key, and the
"sign" sub-commands of --edit-key by forcing the creation
of a key signature, even if one already exists.
- --allow-secret-key-import
- This is an obsolete option and is not used anywhere.
- --allow-multiple-messages
- --no-allow-multiple-messages
- These are obsolete options; they have no more effect since GnuPG 2.2.8.
- --enable-special-filenames
- This option enables a mode in which filenames of the form
‘-&n’, where n is a non-negative decimal number,
refer to the file descriptor n and not to a file with that name.
- --no-expensive-trust-checks
- Experimental use only.
- --preserve-permissions
- Don't change the permissions of a secret keyring back to user read/write
only. Use this option only if you really know what you are doing.
- --default-preference-list string
- Set the list of default preferences to string. This preference list
is used for new keys and becomes the default for "setpref" in
the --edit-key menu.
- --default-keyserver-url name
- Set the default keyserver URL to name. This keyserver will be used
as the keyserver URL when writing a new self-signature on a key, which
includes key generation and changing preferences.
- --list-config
- Display various internal configuration parameters of GnuPG. This option is
intended for external programs that call GnuPG to perform tasks, and is
thus not generally useful. See the file ‘doc/DETAILS’
in the source distribution for the details of which configuration items
may be listed. --list-config is only usable with
--with-colons set.
- --list-gcrypt-config
- Display various internal configuration parameters of Libgcrypt.
- --gpgconf-list
- This command is similar to --list-config but in general only
internally used by the gpgconf tool.
- --gpgconf-test
- This is more or less dummy action. However it parses the configuration
file and returns with failure if the configuration file would prevent
gpg2 from startup. Thus it may be used to run a syntax check on the
configuration file.
- --chuid uid
- Change the current user to uid which may either be a number or a
name. This can be used from the root account to run gpg for another user.
If uid is not the current UID a standard PATH is set and the envvar
GNUPGHOME is unset. To override the latter the option --homedir can
be used. This option has only an effect when used on the command line.
This option has currently no effect at all on Windows.
- --show-photos
- --no-show-photos
- Causes --list-keys, --list-signatures,
--list-public-keys, --list-secret-keys, and verifying a
signature to also display the photo ID attached to the key, if any. See
also --photo-viewer. These options are deprecated. Use
--list-options [no-]show-photos and/or --verify-options
[no-]show-photos instead.
- --show-keyring
- Display the keyring name at the head of key listings to show which keyring
a given key resides on. This option is deprecated: use --list-options
[no-]show-keyring instead.
- --always-trust
- Identical to --trust-model always. This option is deprecated.
- --show-notation
- --no-show-notation
- Show signature notations in the --list-signatures or
--check-signatures listings as well as when verifying a signature
with a notation in it. These options are deprecated. Use --list-options
[no-]show-notation and/or --verify-options [no-]show-notation
instead.
- --show-policy-url
- --no-show-policy-url
- Show policy URLs in the --list-signatures or
--check-signatures listings as well as when verifying a signature
with a policy URL in it. These options are deprecated. Use
--list-options [no-]show-policy-url and/or
--verify-options [no-]show-policy-url instead.
- gpg -se -r Bob file
- sign and encrypt for user Bob
- gpg --clear-sign file
- make a cleartext signature
- gpg -sb file
- make a detached signature
- gpg -u 0x12345678 -sb file
- make a detached signature with the key 0x12345678
- gpg --list-keys user_ID
- show keys
- gpg --fingerprint user_ID
- show fingerprint
- gpg --verify pgpfile
- gpg --verify sigfile [datafile]
- Verify the signature of the file but do not output the data unless
requested. The second form is used for detached signatures, where
sigfile is the detached signature (either ASCII armored or binary)
and datafile are the signed data; if this is not given, the name of
the file holding the signed data is constructed by cutting off the
extension (".asc" or ".sig") of sigfile or by
asking the user for the filename. If the option --output is also
used the signed data is written to the file specified by that option; use
- to write the signed data to stdout.
There are different ways to specify a user ID to GnuPG. Some of them are only
valid for gpg others are only good for gpgsm. Here is the entire
list of ways to specify a key:
- By key Id.
- This format is deduced from the length of the string and its content or
0x prefix. The key Id of an X.509 certificate are the low 64 bits
of its SHA-1 fingerprint. The use of key Ids is just a shortcut, for all
automated processing the fingerprint should be used.
When using gpg an exclamation mark (!) may be appended
to force using the specified primary or secondary key and not to try and
calculate which primary or secondary key to use.
The last four lines of the example give the key ID in their
long form as internally used by the OpenPGP protocol. You can see the
long key ID using the option --with-colons.
234567C4
0F34E556E
01347A56A
0xAB123456
234AABBCC34567C4
0F323456784E56EAB
01AB3FED1347A5612
0x234AABBCC34567C4
- By fingerprint.
- This format is deduced from the length of the string and its content or
the 0x prefix. Note, that only the 20 byte version fingerprint is
available with gpgsm (i.e. the SHA-1 hash of the certificate).
When using gpg an exclamation mark (!) may be appended
to force using the specified primary or secondary key and not to try and
calculate which primary or secondary key to use.
The best way to specify a key Id is by using the fingerprint.
This avoids any ambiguities in case that there are duplicated key
IDs.
1234343434343434C434343434343434
123434343434343C3434343434343734349A3434
0E12343434343434343434EAB3484343434343434
0xE12343434343434343434EAB3484343434343434
gpgsm also accepts colons between each pair of hexadecimal
digits because this is the de-facto standard on how to present X.509
fingerprints. gpg also allows the use of the space separated SHA-1
fingerprint as printed by the key listing commands.
- By exact match on OpenPGP user ID.
- This is denoted by a leading equal sign. It does not make sense for X.509
certificates.
=Heinrich Heine <heinrichh@uni-duesseldorf.de>
- By exact match on an email address.
- This is indicated by enclosing the email address in the usual way with
left and right angles.
<heinrichh@uni-duesseldorf.de>
- By partial match on an email address.
- This is indicated by prefixing the search string with an @. This
uses a substring search but considers only the mail address (i.e. inside
the angle brackets).
- By exact match on the subject's DN.
- This is indicated by a leading slash, directly followed by the RFC-2253
encoded DN of the subject. Note that you can't use the string printed by
gpgsm --list-keys because that one has been reordered and modified
for better readability; use --with-colons to print the raw (but
standard escaped) RFC-2253 string.
/CN=Heinrich Heine,O=Poets,L=Paris,C=FR
- By exact match on the issuer's DN.
- This is indicated by a leading hash mark, directly followed by a slash and
then directly followed by the RFC-2253 encoded DN of the issuer. This
should return the Root cert of the issuer. See note above.
#/CN=Root Cert,O=Poets,L=Paris,C=FR
- By exact match on serial number and issuer's DN.
- This is indicated by a hash mark, followed by the hexadecimal
representation of the serial number, then followed by a slash and the
RFC-2253 encoded DN of the issuer. See note above.
#4F03/CN=Root Cert,O=Poets,L=Paris,C=FR
- By keygrip.
- This is indicated by an ampersand followed by the 40 hex digits of a
keygrip. gpgsm prints the keygrip when using the command
--dump-cert.
&D75F22C3F86E355877348498CDC92BD21010A480
- By substring match.
- This is the default mode but applications may want to explicitly indicate
this by putting the asterisk in front. Match is not case sensitive.
- . and + prefixes
- These prefixes are reserved for looking up mails anchored at the end and
for a word search mode. They are not yet implemented and using them is
undefined.
Please note that we have reused the hash mark identifier which
was used in old GnuPG versions to indicate the so called local-id. It is
not anymore used and there should be no conflict when used with X.509
stuff.
Using the RFC-2253 format of DNs has the drawback that it is
not possible to map them back to the original encoding, however we don't
have to do this because our key database stores this encoding as meta
data.
The options --import-filter and --export-filter use expressions
with this syntax (square brackets indicate an optional part and curly braces a
repetition, white space between the elements are allowed):
[lc] {[{flag}] PROPNAME op VALUE [lc]}
The name of a property (PROPNAME) may only consist of
letters, digits and underscores. The description for the filter type
describes which properties are defined. If an undefined property is used it
evaluates to the empty string. Unless otherwise noted, the VALUE must
always be given and may not be the empty string. No quoting is defined for
the value, thus the value may not contain the strings && or
||, which are used as logical connection operators. The flag
-- can be used to remove this restriction.
Numerical values are computed as long int; standard C notation
applies. lc is the logical connection operator; either
&& for a conjunction or || for a disjunction. A
conjunction is assumed at the begin of an expression. Conjunctions have
higher precedence than disjunctions. If VALUE starts with one of the
characters used in any op a space after the op is
required.
The supported operators (op) are:
- =~
- Substring must match.
- !~
- Substring must not match.
- =
- The full string must match.
- <>
- The full string must not match.
- ==
- The numerical value must match.
- !=
- The numerical value must not match.
- <=
- The numerical value of the field must be LE than the value.
- <
- The numerical value of the field must be LT than the value.
- >
- The numerical value of the field must be GT than the value.
- >=
- The numerical value of the field must be GE than the value.
- -le
- The string value of the field must be less or equal than the value.
- -lt
- The string value of the field must be less than the value.
- -gt
- The string value of the field must be greater than the value.
- -ge
- The string value of the field must be greater or equal than the value.
- -n
- True if value is not empty (no value allowed).
- -z
- True if value is empty (no value allowed).
- -t
- Alias for "PROPNAME != 0" (no value allowed).
- -f
- Alias for "PROPNAME == 0" (no value allowed).
Values for flag must be space separated. The supported
flags are:
- --
- VALUE spans to the end of the expression.
- -c
- The string match in this part is done case-sensitive.
- -t
- Leading and trailing spaces are not removed from VALUE. The
optional single space after op is here required.
The filter options concatenate several specifications for a filter
of the same type. For example the four options in this example:
--import-filter keep-uid="uid =~ Alfa"
--import-filter keep-uid="&& uid !~ Test"
--import-filter keep-uid="|| uid =~ Alpha"
--import-filter keep-uid="uid !~ Test"
which is equivalent to
--import-filter \
keep-uid="uid =~ Alfa" && uid !~ Test" || uid =~ Alpha" && "uid !~ Test"
imports only the user ids of a key containing the strings
"Alfa" or "Alpha" but not the string
"test".
Trust values are used to indicate ownertrust and validity of keys and user IDs.
They are displayed with letters or strings:
- -
- unknown
- No ownertrust assigned / not yet calculated.
- e
- expired
-
Trust calculation has failed; probably due to an expired
key.
- q
- undefined, undef
- Not enough information for calculation.
- n
- never
- Never trust this key.
- m
- marginal
- Marginally trusted.
- f
- full
- Fully trusted.
- u
- ultimate
- Ultimately trusted.
- r
- revoked
- For validity only: the key or the user ID has been revoked.
- ?
- err
- The program encountered an unknown trust value.
There are a few configuration files to control certain aspects of gpg2's
operation. Unless noted, they are expected in the current home directory (see:
[option --homedir]).
- gpg.conf
- This is the standard configuration file read by gpg2 on startup. It
may contain any valid long option; the leading two dashes may not be
entered and the option may not be abbreviated. This default name may be
changed on the command line (see: [gpg-option --options]). You should
backup this file.
- common.conf
- This is an optional configuration file read by gpg2 on startup. It
may contain options pertaining to all components of GnuPG. Its current
main use is for the "use-keyboxd" option.
Note that on larger installations, it is useful to put predefined
files into the directory ‘/usr/local/etc/skel/.gnupg’
so that newly created users start up with a working configuration. For
existing users a small helper script is provided to create these files (see:
[addgnupghome]).
For internal purposes gpg2 creates and maintains a few
other files; They all live in the current home directory (see: [option
--homedir]). Only the gpg2 program may modify these files.
- ~/.gnupg
- This is the default home directory which is used if neither the
environment variable GNUPGHOME nor the option --homedir is
given.
- ~/.gnupg/pubring.gpg
- The public keyring using a legacy format. You should backup this file.
If this file is not available, gpg defaults to the new
keybox format and creates a file ‘pubring.kbx’
unless that file already exists in which case that file will also be
used for OpenPGP keys.
Note that in the case that both files,
‘pubring.gpg’ and
‘pubring.kbx’ exists but the latter has no OpenPGP
keys, the legacy file ‘pubring.gpg’ will be used.
Take care: GnuPG versions before 2.1 will always use the file
‘pubring.gpg’ because they do not know about the
new keybox format. In the case that you have to use GnuPG 1.4 to decrypt
archived data you should keep this file.
- ~/.gnupg/pubring.gpg.lock
- The lock file for the public keyring.
- ~/.gnupg/pubring.kbx
- The public keyring using the new keybox format. This file is shared with
gpgsm. You should backup this file. See above for the relation
between this file and it predecessor.
To convert an existing ‘pubring.gpg’ file
to the keybox format, you first backup the ownertrust values, then
rename ‘pubring.gpg’ to
‘publickeys.backup’, so it won’t be
recognized by any GnuPG version, run import, and finally restore the
ownertrust values:
$ cd ~/.gnupg
$ gpg --export-ownertrust >otrust.lst
$ mv pubring.gpg publickeys.backup
$ gpg --import-options restore --import publickeys.backups
$ gpg --import-ownertrust otrust.lst
- ~/.gnupg/pubring.kbx.lock
- The lock file for ‘pubring.kbx’.
- ~/.gnupg/secring.gpg
- The legacy secret keyring as used by GnuPG versions before 2.1. It is not
used by GnuPG 2.1 and later. You may want to keep it in case you have to
use GnuPG 1.4 to decrypt archived data.
- ~/.gnupg/secring.gpg.lock
- The lock file for the legacy secret keyring.
- ~/.gnupg/.gpg-v21-migrated
- File indicating that a migration to GnuPG 2.1 has been done.
- ~/.gnupg/trustdb.gpg
- The trust database. There is no need to backup this file; it is better to
backup the ownertrust values (see: [option --export-ownertrust]).
- ~/.gnupg/trustdb.gpg.lock
- The lock file for the trust database.
- ~/.gnupg/random_seed
- A file used to preserve the state of the internal random pool.
- ~/.gnupg/openpgp-revocs.d/
- This is the directory where gpg stores pre-generated revocation
certificates. The file name corresponds to the OpenPGP fingerprint of the
respective key. It is suggested to backup those certificates and if the
primary private key is not stored on the disk to move them to an external
storage device. Anyone who can access these files is able to revoke the
corresponding key. You may want to print them out. You should backup all
files in this directory and take care to keep this backup closed away.
Operation is further controlled by a few environment
variables:
- HOME
- Used to locate the default home directory.
- GNUPGHOME
- If set directory used instead of "~/.gnupg".
- GPG_AGENT_INFO
- This variable is obsolete; it was used by GnuPG versions before 2.1.
- PINENTRY_USER_DATA
- This value is passed via gpg-agent to pinentry. It is useful to convey
extra information to a custom pinentry.
- COLUMNS
- LINES
- Used to size some displays to the full size of the screen.
- LANGUAGE
- Apart from its use by GNU, it is used in the W32 version to override the
language selection done through the Registry. If used and set to a valid
and available language name (langid), the file with the translation
is loaded from gpgdir/gnupg.nls/langid.mo. Here
gpgdir is the directory out of which the gpg binary has been
loaded. If it can't be loaded the Registry is tried and as last resort the
native Windows locale system is used.
- GNUPG_BUILD_ROOT
- This variable is only used by the regression test suite as a helper under
operating systems without proper support to figure out the name of a
process' text file.
When calling the gpg-agent component gpg2 sends a set of
environment variables to gpg-agent. The names of these variables can be
listed using the command:
gpg-connect-agent 'getinfo std_env_names' /bye | awk '$1=="D" {print $2}'
On older systems this program should be installed as setuid(root). This is
necessary to lock memory pages. Locking memory pages prevents the operating
system from writing memory pages (which may contain passphrases or other
sensitive material) to disk. If you get no warning message about insecure
memory your operating system supports locking without being root. The program
drops root privileges as soon as locked memory is allocated.
Note also that some systems (especially laptops) have the ability
to ``suspend to disk'' (also known as ``safe sleep'' or ``hibernate''). This
writes all memory to disk before going into a low power or even powered off
mode. Unless measures are taken in the operating system to protect the saved
memory, passphrases or other sensitive material may be recoverable from it
later.
Before you report a bug you should first search the mailing list
archives for similar problems and second check whether such a bug has
already been reported to our bug tracker at
https://bugs.gnupg.org.
gpgv(1), gpgsm(1), gpg-agent(1)
The full documentation for this tool is maintained as a Texinfo
manual. If GnuPG and the info program are properly installed at your site,
the command
should give you access to the complete manual including a menu
structure and an index.
Visit the GSP FreeBSD Man Page Interface. Output converted with ManDoc. |