NAME

SYNOPSIS

    % cpansign              # verify an existing SIGNATURE, or
                            # make a new one if none exists

    % cpansign sign         # make signature; overwrites existing one
    % cpansign -s           # same thing

    % cpansign verify       # verify a signature
    % cpansign -v           # same thing
    % cpansign -v --skip    # ignore files in MANIFEST.SKIP

    % cpansign help         # display this documentation
    % cpansign -h           # same thing

In programs:

    use Module::Signature qw(sign verify SIGNATURE_OK);
    sign();
    sign(overwrite => 1);       # overwrites without asking

    # see the CONSTANTS section below
    (verify() == SIGNATURE_OK) or die "failed!";

DESCRIPTION

If you are a module user, all you have to do is to remember to run "cpansign -v" (or just "cpansign") before issuing "perl Makefile.PL" or "perl Build.PL"; that will ensure the distribution has not been tampered with.

Module authors can easily add the SIGNATURE file to the distribution tarball; see "NOTES" below for how to do it as part of "make dist".

If you really want to sign a distribution manually, simply add "SIGNATURE" to MANIFEST, then type "cpansign -s" immediately before "make dist". Be sure to delete the SIGNATURE file afterwards.

Please also see "NOTES" about MANIFEST.SKIP issues, especially if you are using Module::Build or writing your own MANIFEST.SKIP.

Signatures made with Module::Signature prior to version 0.82 used the SHA1 algorithm by default. SHA1 is now considered broken, and therefore module authors are strongly encouraged to regenerate their SIGNATURE files. Users verifying old SHA1 signature files will receive a warning.

VARIABLES

$Verbose

If true, Module::Signature will give information during processing including gpg output. If false, Module::Signature will be as quiet as possible as long as everything is working ok. Defaults to false.

$SIGNATURE

The filename for a distribution's signature file. Defaults to "SIGNATURE".

$AUTHOR

The key ID used for signature. If empty/null/0, "gpg"'s configured default ID, or the most recently added key within the secret keyring for "Crypt::OpenPGP", will be used for the signature.

$KeyServer

The OpenPGP key server for fetching the author's public key (currently only implemented on "gpg", not "Crypt::OpenPGP"). May be set to a false value to prevent this module from fetching public keys.

$KeyServerPort

The OpenPGP key server port, defaults to 11371.

$Timeout

Maximum time to wait to try to establish a link to the key server. Defaults to 3.

$AutoKeyRetrieve

Whether to automatically fetch unknown keys from the key server. Defaults to 1.

$Cipher

The default cipher used by the "Digest" module to make signature files. Defaults to "SHA256", but may be changed to other ciphers via the "MODULE_SIGNATURE_CIPHER" environment variable if the SHA256 cipher is undesirable for the user.

The cipher specified in the SIGNATURE file's first entry will be used to validate its integrity. For "SHA256", the user needs to have any one of these modules installed: Digest::SHA, Digest::SHA256, or Digest::SHA::PurePerl.

$Preamble

The explanatory text written to newly generated SIGNATURE files before the actual entries.

ENVIRONMENT

MODULE_SIGNATURE_AUTHOR

Works like $AUTHOR.

MODULE_SIGNATURE_CIPHER

Works like $Cipher.

MODULE_SIGNATURE_VERBOSE

Works like $Verbose.

MODULE_SIGNATURE_KEYSERVER

Works like $KeyServer.

MODULE_SIGNATURE_KEYSERVERPORT

Works like $KeyServerPort.

MODULE_SIGNATURE_TIMEOUT

Works like $Timeout.

CONSTANTS

CANNOT_VERIFY (0E0)

Cannot verify the OpenPGP signature, maybe due to the lack of a network connection to the key server, or if neither gnupg nor Crypt::OpenPGP exists on the system.

SIGNATURE_OK (0)

Signature successfully verified.

SIGNATURE_MISSING ("-1")

The SIGNATURE file does not exist.

SIGNATURE_MALFORMED ("-2")

The signature file does not contains a valid OpenPGP message.

SIGNATURE_BAD ("-3")

Invalid signature detected -- it might have been tampered with.

SIGNATURE_MISMATCH ("-4")

The signature is valid, but files in the distribution have changed since its creation.

MANIFEST_MISMATCH ("-5")

There are extra files in the current directory not specified by the MANIFEST file.

CIPHER_UNKNOWN ("-6")

The cipher used by the signature file is not recognized by the "Digest" and "Digest::*" modules.

NOTES

    sign;       # put this before "WriteAll"
    WriteAll;

    WriteMakefile(
        (MM->can('signature_target') ? (SIGN => 1) : ()),
        # ... original arguments ...
    );

    Module::Build->new(
        (sign => 1),
        # ... original arguments ...
    )->create_build_script;

    #defaults
    ^Makefile$
    ^blib/
    ^pm_to_blib
    ^blibdirs

    ^Build$
    ^_build/

    ==> MISMATCHED content between MANIFEST and distribution files! <==

    #!/usr/bin/perl

    use strict;
    print "1..1\n";

    if (!$ENV{TEST_SIGNATURE}) {
        print "ok 1 # skip Set the environment variable",
                    " TEST_SIGNATURE to enable this test\n";
    }
    elsif (!-s 'SIGNATURE') {
        print "ok 1 # skip No signature file found\n";
    }
    elsif (!eval { require Module::Signature; 1 }) {
        print "ok 1 # skip ",
                "Next time around, consider install Module::Signature, ",
                "so you can verify the integrity of this distribution.\n";
    }
    elsif (!eval { require Socket; Socket::inet_aton('pool.sks-keyservers.net') }) {
        print "ok 1 # skip ",
                "Cannot connect to the keyserver\n";
    }
    else {
        (Module::Signature::verify() == Module::Signature::SIGNATURE_OK())
            or print "not ";
        print "ok 1 # Valid signature\n";
    }

    __END__

SEE ALSO

ExtUtils::Manifest, Crypt::OpenPGP, Test::Signature

Module::Install, ExtUtils::MakeMaker, Module::Build

Dist::Zilla::Plugin::Signature

AUTHORS

LICENSE

To the extent possible under law, 唐鳳 has waived all copyright and related or neighboring rights to Module-Signature.

This work is published from Taiwan.

<http://creativecommons.org/publicdomain/zero/1.0>