openssl-ca - sample minimal CA application
openssl ca [-help] [-verbose] [-config
filename] [-name section] [-section
section] [-gencrl] [-revoke file] [-valid
file] [-status serial] [-updatedb]
[-crl_reason reason] [-crl_hold instruction]
[-crl_compromise time] [-crl_CA_compromise time]
[-crl_lastupdate date] [-crl_nextupdate date]
[-crldays days] [-crlhours hours] [-crlsec
seconds] [-crlexts section] [-startdate
date] [-enddate date] [-days arg]
[-md arg] [-policy arg] [-keyfile
filename|uri] [-keyform
DER|PEM|P12|ENGINE] [-key arg]
[-passin arg] [-cert file] [-certform
DER|PEM|P12] [-selfsign] [-in file]
[-inform DER|<PEM>] [-out file]
[-notext] [-dateopt] [-outdir dir]
[-infiles] [-spkac file] [-ss_cert file]
[-preserveDN] [-noemailDN] [-batch] [-msie_hack]
[-extensions section] [-extfile section]
[-subj arg] [-utf8] [-sigopt nm:v]
[-vfyopt nm:v] [-create_serial]
[-rand_serial] [-multivalue-rdn] [-rand files]
[-writerand file] [-engine id] [-provider
name] [-provider-path path] [-propquery
propq] [certreq...]
This command emulates a CA application. See the WARNINGS especially when
considering to use it productively. It can be used to sign certificate
requests (CSRs) in a variety of forms and generate certificate revocation
lists (CRLs). It also maintains a text database of issued certificates and
their status. When signing certificates, a single request can be specified
with the -in option, or multiple requests can be processed by
specifying a set of certreq files after all options.
Note that there are also very lean ways of generating
certificates: the req and x509 commands can be used for
directly creating certificates. See openssl-req(1) and
openssl-x509(1) for details.
The descriptions of the ca command options are divided into
each purpose.
- -help
- Print out a usage message.
- -verbose
- This prints extra details about the operations being performed.
- -config filename
- Specifies the configuration file to use. Optional; for a description of
the default value, see "COMMAND SUMMARY" in
openssl(1).
- -name section, -section section
- Specifies the configuration file section to use (overrides
default_ca in the ca section).
- -in filename
- An input filename containing a single certificate request (CSR) to be
signed by the CA.
- -inform DER|PEM
- The format of the data in certificate request input files; unspecified by
default. See openssl-format-options(1) for details.
- -ss_cert filename
- A single self-signed certificate to be signed by the CA.
- -spkac filename
- A file containing a single Netscape signed public key and challenge and
additional field values to be signed by the CA. See the SPKAC
FORMAT section for information on the required input and output
format.
- -infiles
- If present this should be the last option, all subsequent arguments are
taken as the names of files containing certificate requests.
- -out filename
- The output file to output certificates to. The default is standard output.
The certificate details will also be printed out to this file in PEM
format (except that -spkac outputs DER format).
- -outdir directory
- The directory to output certificates to. The certificate will be written
to a filename consisting of the serial number in hex with .pem
appended.
- -cert filename
- The CA certificate, which must match with -keyfile.
- -certform DER|PEM|P12
- The format of the data in certificate input files; unspecified by default.
See openssl-format-options(1) for details.
- -keyfile filename|uri
- The CA private key to sign certificate requests with. This must match with
-cert.
- -keyform DER|PEM|P12|ENGINE
- The format of the private key input file; unspecified by default. See
openssl-format-options(1) for details.
- -sigopt nm:v
- Pass options to the signature algorithm during sign operations. Names and
values of these options are algorithm-specific.
- -vfyopt nm:v
- Pass options to the signature algorithm during verify operations. Names
and values of these options are algorithm-specific.
This often needs to be given while signing too, because the
self-signature of a certificate signing request (CSR) is verified
against the included public key, and that verification may need its own
set of options.
- -key password
- The password used to encrypt the private key. Since on some systems the
command line arguments are visible (e.g., when using ps(1) on
Unix), this option should be used with caution. Better use
-passin.
- -passin arg
- The key password source for key files and certificate PKCS#12 files. For
more information about the format of arg see
openssl-passphrase-options(1).
- -selfsign
- Indicates the issued certificates are to be signed with the key the
certificate requests were signed with (given with -keyfile).
Certificate requests signed with a different key are ignored. If
-spkac, -ss_cert or -gencrl are given,
-selfsign is ignored.
A consequence of using -selfsign is that the
self-signed certificate appears among the entries in the certificate
database (see the configuration option database), and uses the
same serial number counter as all other certificates sign with the
self-signed certificate.
- -notext
- Don't output the text form of a certificate to the output file.
- -dateopt
- Specify the date output format. Values are: rfc_822 and iso_8601. Defaults
to rfc_822.
- -startdate date
- This allows the start date to be explicitly set. The format of the date is
YYMMDDHHMMSSZ (the same as an ASN1 UTCTime structure), or YYYYMMDDHHMMSSZ
(the same as an ASN1 GeneralizedTime structure). In both formats, seconds
SS and timezone Z must be present.
- -enddate date
- This allows the expiry date to be explicitly set. The format of the date
is YYMMDDHHMMSSZ (the same as an ASN1 UTCTime structure), or
YYYYMMDDHHMMSSZ (the same as an ASN1 GeneralizedTime structure). In both
formats, seconds SS and timezone Z must be present.
- -days arg
- The number of days to certify the certificate for.
- -md alg
- The message digest to use. Any digest supported by the
openssl-dgst(1) command can be used. For signing algorithms that do
not support a digest (i.e. Ed25519 and Ed448) any message digest that is
set is ignored. This option also applies to CRLs.
- -policy arg
- This option defines the CA "policy" to use. This is a section in
the configuration file which decides which fields should be mandatory or
match the CA certificate. Check out the POLICY FORMAT section for
more information.
- -msie_hack
- This is a deprecated option to make this command work with very old
versions of the IE certificate enrollment control "certenr3". It
used UniversalStrings for almost everything. Since the old control has
various security bugs its use is strongly discouraged.
- -preserveDN
- Normally the DN order of a certificate is the same as the order of the
fields in the relevant policy section. When this option is set the order
is the same as the request. This is largely for compatibility with the
older IE enrollment control which would only accept certificates if their
DNs match the order of the request. This is not needed for Xenroll.
- -noemailDN
- The DN of a certificate can contain the EMAIL field if present in the
request DN, however, it is good policy just having the e-mail set into the
altName extension of the certificate. When this option is set the EMAIL
field is removed from the certificate' subject and set only in the,
eventually present, extensions. The email_in_dn keyword can be used
in the configuration file to enable this behaviour.
- -batch
- This sets the batch mode. In this mode no questions will be asked and all
certificates will be certified automatically.
- -extensions section
- The section of the configuration file containing certificate extensions to
be added when a certificate is issued (defaults to x509_extensions
unless the -extfile option is used). If no X.509 extensions are
specified then a V1 certificate is created, else a V3 certificate is
created. See the x509v3_config(5) manual page for details of the
extension section format.
- -extfile file
- An additional configuration file to read certificate extensions from
(using the default section unless the -extensions option is also
used).
- -subj arg
- Supersedes subject name given in the request.
The arg must be formatted as
"/type0=value0/type1=value1/type2=...".
Special characters may be escaped by
"\" (backslash), whitespace is
retained. Empty values are permitted, but the corresponding type will
not be included in the resulting certificate. Giving a single
"/" will lead to an empty sequence of
RDNs (a NULL-DN). Multi-valued RDNs can be formed by placing a
"+" character instead of a
"/" between the
AttributeValueAssertions (AVAs) that specify the members of the set.
Example:
"/DC=org/DC=OpenSSL/DC=users/UID=123456+CN=John
Doe"
- -utf8
- This option causes field values to be interpreted as UTF8 strings, by
default they are interpreted as ASCII. This means that the field values,
whether prompted from a terminal or obtained from a configuration file,
must be valid UTF8 strings.
- -create_serial
- If reading serial from the text file as specified in the configuration
fails, specifying this option creates a new random serial to be used as
next serial number. To get random serial numbers, use the
-rand_serial flag instead; this should only be used for simple
error-recovery.
- -rand_serial
- Generate a large random number to use as the serial number. This overrides
any option or configuration to use a serial number file.
- -multivalue-rdn
- This option has been deprecated and has no effect.
- -rand files, -writerand file
- See "Random State Options" in openssl(1) for
details.
- -engine id
- See "Engine Options" in openssl(1). This option is
deprecated.
- -provider name
- -provider-path path
- -propquery propq
- See "Provider Options" in openssl(1), provider(7),
and property(7).
- -gencrl
- This option generates a CRL based on information in the index file.
- -crl_lastupdate time
- Allows the value of the CRL's lastUpdate field to be explicitly set; if
this option is not present, the current time is used. Accepts times in
YYMMDDHHMMSSZ format (the same as an ASN1 UTCTime structure) or
YYYYMMDDHHMMSSZ format (the same as an ASN1 GeneralizedTime
structure).
- -crl_nextupdate time
- Allows the value of the CRL's nextUpdate field to be explicitly set; if
this option is present, any values given for -crldays,
-crlhours and -crlsec are ignored. Accepts times in the same
formats as -crl_lastupdate.
- -crldays num
- The number of days before the next CRL is due. That is the days from now
to place in the CRL nextUpdate field.
- -crlhours num
- The number of hours before the next CRL is due.
- -crlsec num
- The number of seconds before the next CRL is due.
- -revoke filename
- A filename containing a certificate to revoke.
- -valid filename
- A filename containing a certificate to add a Valid certificate entry.
- -status serial
- Displays the revocation status of the certificate with the specified
serial number and exits.
- -updatedb
- Updates the database index to purge expired certificates.
- -crl_reason reason
- Revocation reason, where reason is one of: unspecified,
keyCompromise, CACompromise, affiliationChanged,
superseded, cessationOfOperation, certificateHold or
removeFromCRL. The matching of reason is case insensitive.
Setting any revocation reason will make the CRL v2.
In practice removeFromCRL is not particularly useful
because it is only used in delta CRLs which are not currently
implemented.
- -crl_hold instruction
- This sets the CRL revocation reason code to certificateHold and the
hold instruction to instruction which must be an OID. Although any
OID can be used only holdInstructionNone (the use of which is
discouraged by RFC2459) holdInstructionCallIssuer or
holdInstructionReject will normally be used.
- -crl_compromise time
- This sets the revocation reason to keyCompromise and the compromise
time to time. time should be in GeneralizedTime format that
is YYYYMMDDHHMMSSZ.
- -crl_CA_compromise time
- This is the same as crl_compromise except the revocation reason is
set to CACompromise.
- -crlexts section
- The section of the configuration file containing CRL extensions to
include. If no CRL extension section is present then a V1 CRL is created,
if the CRL extension section is present (even if it is empty) then a V2
CRL is created. The CRL extensions specified are CRL extensions and
not CRL entry extensions. It should be noted that some software
(for example Netscape) can't handle V2 CRLs. See x509v3_config(5)
manual page for details of the extension section format.
The section of the configuration file containing options for this command is
found as follows: If the -name command line option is used, then it
names the section to be used. Otherwise the section to be used must be named
in the default_ca option of the ca section of the configuration
file (or in the default section of the configuration file). Besides
default_ca, the following options are read directly from the ca
section:
RANDFILE
preserve
msie_hack With the exception of RANDFILE, this is probably a bug and may
change in future releases.
Many of the configuration file options are identical to command
line options. Where the option is present in the configuration file and the
command line the command line value is used. Where an option is described as
mandatory then it must be present in the configuration file or the command
line equivalent (if any) used.
- oid_file
- This specifies a file containing additional OBJECT IDENTIFIERS.
Each line of the file should consist of the numerical form of the object
identifier followed by whitespace then the short name followed by
whitespace and finally the long name.
- oid_section
- This specifies a section in the configuration file containing extra object
identifiers. Each line should consist of the short name of the object
identifier followed by = and the numerical form. The short and long
names are the same when this option is used.
- new_certs_dir
- The same as the -outdir command line option. It specifies the
directory where new certificates will be placed. Mandatory.
- certificate
- The same as -cert. It gives the file containing the CA certificate.
Mandatory.
- private_key
- Same as the -keyfile option. The file containing the CA private
key. Mandatory.
- RANDFILE
- At startup the specified file is loaded into the random number generator,
and at exit 256 bytes will be written to it. (Note: Using a RANDFILE is
not necessary anymore, see the "HISTORY" section.
- default_days
- The same as the -days option. The number of days to certify a
certificate for.
- default_startdate
- The same as the -startdate option. The start date to certify a
certificate for. If not set the current time is used.
- default_enddate
- The same as the -enddate option. Either this option or
default_days (or the command line equivalents) must be
present.
- default_crl_hours default_crl_days
- The same as the -crlhours and the -crldays options. These
will only be used if neither command line option is present. At least one
of these must be present to generate a CRL.
- default_md
- The same as the -md option. Mandatory except where the signing
algorithm does not require a digest (i.e. Ed25519 and Ed448).
- database
- The text database file to use. Mandatory. This file must be present though
initially it will be empty.
- unique_subject
- If the value yes is given, the valid certificate entries in the
database must have unique subjects. if the value no is given,
several valid certificate entries may have the exact same subject. The
default value is yes, to be compatible with older (pre 0.9.8)
versions of OpenSSL. However, to make CA certificate roll-over easier,
it's recommended to use the value no, especially if combined with
the -selfsign command line option.
Note that it is valid in some circumstances for certificates
to be created without any subject. In the case where there are multiple
certificates without subjects this does not count as a duplicate.
- serial
- A text file containing the next serial number to use in hex. Mandatory.
This file must be present and contain a valid serial number.
- crlnumber
- A text file containing the next CRL number to use in hex. The crl number
will be inserted in the CRLs only if this file exists. If this file is
present, it must contain a valid CRL number.
- x509_extensions
- A fallback to the -extensions option.
- crl_extensions
- A fallback to the -crlexts option.
- preserve
- The same as -preserveDN
- email_in_dn
- The same as -noemailDN. If you want the EMAIL field to be removed
from the DN of the certificate simply set this to 'no'. If not present the
default is to allow for the EMAIL filed in the certificate's DN.
- msie_hack
- The same as -msie_hack
- policy
- The same as -policy. Mandatory. See the POLICY FORMAT
section for more information.
- name_opt, cert_opt
- These options allow the format used to display the certificate details
when asking the user to confirm signing. All the options supported by the
x509 utilities -nameopt and -certopt switches can be
used here, except the no_signame and no_sigdump are
permanently set and cannot be disabled (this is because the certificate
signature cannot be displayed because the certificate has not been signed
at this point).
For convenience the values ca_default are accepted by
both to produce a reasonable output.
If neither option is present the format used in earlier
versions of OpenSSL is used. Use of the old format is strongly
discouraged because it only displays fields mentioned in the
policy section, mishandles multicharacter string types and does
not display extensions.
- copy_extensions
- Determines how extensions in certificate requests should be handled. If
set to none or this option is not present then extensions are
ignored and not copied to the certificate. If set to copy then any
extensions present in the request that are not already present are copied
to the certificate. If set to copyall then all extensions in the
request are copied to the certificate: if the extension is already present
in the certificate it is deleted first. See the WARNINGS section
before using this option.
The main use of this option is to allow a certificate request
to supply values for certain extensions such as subjectAltName.
The policy section consists of a set of variables corresponding to certificate
DN fields. If the value is "match" then the field value must match
the same field in the CA certificate. If the value is "supplied"
then it must be present. If the value is "optional" then it may be
present. Any fields not mentioned in the policy section are silently deleted,
unless the -preserveDN option is set but this can be regarded more of a
quirk than intended behaviour.
The input to the -spkac command line option is a Netscape signed public
key and challenge. This will usually come from the KEYGEN tag in an
HTML form to create a new private key. It is however possible to create SPKACs
using openssl-spkac(1).
The file should contain the variable SPKAC set to the value of the
SPKAC and also the required DN components as name value pairs. If you need
to include the same component twice then it can be preceded by a number and
a '.'.
When processing SPKAC format, the output is DER if the -out
flag is used, but PEM format if sending to stdout or the -outdir flag
is used.
Note: these examples assume that the directory structure this command assumes is
already set up and the relevant files already exist. This usually involves
creating a CA certificate and private key with openssl-req(1), a serial
number file and an empty index file and placing them in the relevant
directories.
To use the sample configuration file below the directories
demoCA, demoCA/private and demoCA/newcerts would be
created. The CA certificate would be copied to demoCA/cacert.pem and
its private key to demoCA/private/cakey.pem. A file
demoCA/serial would be created containing for example "01"
and the empty index file demoCA/index.txt.
Sign a certificate request:
openssl ca -in req.pem -out newcert.pem
Sign an SM2 certificate request:
openssl ca -in sm2.csr -out sm2.crt -md sm3 \
-sigopt "distid:1234567812345678" \
-vfyopt "distid:1234567812345678"
Sign a certificate request, using CA extensions:
openssl ca -in req.pem -extensions v3_ca -out newcert.pem
Generate a CRL
openssl ca -gencrl -out crl.pem
Sign several requests:
openssl ca -infiles req1.pem req2.pem req3.pem
Certify a Netscape SPKAC:
openssl ca -spkac spkac.txt
A sample SPKAC file (the SPKAC line has been truncated for
clarity):
SPKAC=MIG0MGAwXDANBgkqhkiG9w0BAQEFAANLADBIAkEAn7PDhCeV/xIxUg8V70YRxK2A5
CN=Steve Test
emailAddress=steve@openssl.org
0.OU=OpenSSL Group
1.OU=Another Group
A sample configuration file with the relevant sections for this
command:
[ ca ]
default_ca = CA_default # The default ca section
[ CA_default ]
dir = ./demoCA # top dir
database = $dir/index.txt # index file.
new_certs_dir = $dir/newcerts # new certs dir
certificate = $dir/cacert.pem # The CA cert
serial = $dir/serial # serial no file
#rand_serial = yes # for random serial#'s
private_key = $dir/private/cakey.pem# CA private key
default_days = 365 # how long to certify for
default_crl_days= 30 # how long before next CRL
default_md = md5 # md to use
policy = policy_any # default policy
email_in_dn = no # Don't add the email into cert DN
name_opt = ca_default # Subject name display option
cert_opt = ca_default # Certificate display option
copy_extensions = none # Don't copy extensions from request
[ policy_any ]
countryName = supplied
stateOrProvinceName = optional
organizationName = optional
organizationalUnitName = optional
commonName = supplied
emailAddress = optional
Note: the location of all files can change either by compile time options,
configuration file entries, environment variables or command line options. The
values below reflect the default values.
/usr/local/ssl/lib/openssl.cnf - master configuration file
./demoCA - main CA directory
./demoCA/cacert.pem - CA certificate
./demoCA/private/cakey.pem - CA private key
./demoCA/serial - CA serial number file
./demoCA/serial.old - CA serial number backup file
./demoCA/index.txt - CA text database file
./demoCA/index.txt.old - CA text database backup file
./demoCA/certs - certificate output file
The text database index file is a critical part of the process and if corrupted
it can be difficult to fix. It is theoretically possible to rebuild the index
file from all the issued certificates and a current CRL: however there is no
option to do this.
V2 CRL features like delta CRLs are not currently supported.
Although several requests can be input and handled at once it is
only possible to include one SPKAC or self-signed certificate.
This command is quirky and at times downright unfriendly.
The use of an in-memory text database can cause problems when
large numbers of certificates are present because, as the name implies the
database has to be kept in memory.
This command really needs rewriting or the required functionality
exposed at either a command or interface level so that a more user-friendly
replacement could handle things properly. The script CA.pl helps a
little but not very much.
Any fields in a request that are not present in a policy are
silently deleted. This does not happen if the -preserveDN option is
used. To enforce the absence of the EMAIL field within the DN, as suggested
by RFCs, regardless the contents of the request' subject the
-noemailDN option can be used. The behaviour should be more friendly
and configurable.
Canceling some commands by refusing to certify a certificate can
create an empty file.
This command was originally meant as an example of how to do things in a CA. Its
code does not have production quality. It was not supposed to be used as a
full blown CA itself, nevertheless some people are using it for this purpose
at least internally. When doing so, specific care should be taken to properly
secure the private key(s) used for signing certificates. It is advisable to
keep them in a secure HW storage such as a smart card or HSM and access them
via a suitable engine or crypto provider.
This command command is effectively a single user command: no
locking is done on the various files and attempts to run more than one
openssl ca command on the same database can have unpredictable
results.
The copy_extensions option should be used with caution. If
care is not taken then it can be a security risk. For example if a
certificate request contains a basicConstraints extension with CA:TRUE and
the copy_extensions value is set to copyall and the user does
not spot this when the certificate is displayed then this will hand the
requester a valid CA certificate. This situation can be avoided by setting
copy_extensions to copy and including basicConstraints with
CA:FALSE in the configuration file. Then if the request contains a
basicConstraints extension it will be ignored.
It is advisable to also include values for other extensions such
as keyUsage to prevent a request supplying its own values.
Additional restrictions can be placed on the CA certificate
itself. For example if the CA certificate has:
basicConstraints = CA:TRUE, pathlen:0
then even if a certificate is issued with CA:TRUE it will not be
valid.
Since OpenSSL 1.1.1, the program follows RFC5280. Specifically, certificate
validity period (specified by any of -startdate, -enddate and
-days) and CRL last/next update time (specified by any of
-crl_lastupdate, -crl_nextupdate, -crldays,
-crlhours and -crlsec) will be encoded as UTCTime if the dates
are earlier than year 2049 (included), and as GeneralizedTime if the dates are
in year 2050 or later.
OpenSSL 1.1.1 introduced a new random generator (CSPRNG) with an
improved seeding mechanism. The new seeding mechanism makes it unnecessary
to define a RANDFILE for saving and restoring randomness. This option is
retained mainly for compatibility reasons.
The -section option was added in OpenSSL 3.0.0.
The -multivalue-rdn option has become obsolete in OpenSSL
3.0.0 and has no effect.
The -engine option was deprecated in OpenSSL 3.0.
openssl(1), openssl-req(1), openssl-spkac(1),
openssl-x509(1), CA.pl(1), config(5),
x509v3_config(5)
Copyright 2000-2021 The OpenSSL Project Authors. All Rights Reserved.
Licensed under the Apache License 2.0 (the "License").
You may not use this file except in compliance with the License. You can
obtain a copy in the file LICENSE in the source distribution or at
<https://www.openssl.org/source/license.html>.