# PGP::Sign

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Copyright 1997-2000, 2002, 2004, 2018, 2020 Russ Allbery <rra@cpan.org>.
This software is distributed under the same terms as Perl itself.  Please
see the section [License](#license) below for more information.

## Blurb

PGP::Sign is a Perl module for generating and verifying detached OpenPGP
signatures of textual data using GnuPG.  It was written to support Netnews
article signatures for signed control messages and PGPMoose.

## Description

PGP::Sign is a Perl module that can generate and verify OpenPGP signatures
on some data.  Currently, only textual data (data that can be processed
using GnuPG's `--textmode` option) is supported.  It uses GnuPG under the
hood to do the work.

The original purpose of this module was to factor out common code in a
News::Article class written by Andrew Gierth that handled PGPMoose and
control message signatures.  It is used to verify control message
signatures for the ftp.isc.org Netnews metadata archive, and to generate
signed control messages for the Big Eight Usenet hierarchies.

Data to be signed or verified can be passed into PGP::Sign in a wide
variety of formats: scalars, arrays, open files, even code references that
act as generators.  Keys with passphrases are supported and the passphrase
is passed to GnuPG securely (although getting the passphrase to the
PGP::Sign module is a problem for the calling application).

This module supports both GnuPG v2 and GnuPG v1 and, when used with GnuPG
v1, supports using OpenPGP keys and generating and verifying signatures
that are backward-compatible with PGP 2.6.2.

PGP::Sign provides both a (recommended) object-oriented API and a (legacy)
function-based API that uses global variables for configuration and is
backward-compatible with earlier versions of PGP::Sign.

## Requirements

Perl 5.20 or later and Module::Build are required to build this module,
and IPC::Run is required to use it.  Either GnuPG v2 or GnuPG v1
(selectable at runtime) is also required.  It has not been tested with
versions of GnuPG older than 1.4.23.

PGP::Sign uses IPC::Run features that are documented as not available on
Windows (primarily higher-numbered file descriptors) and has never been
tested with Gpg4win, so will probably not work on Windows (or, for that
matter, other non-UNIX systems).

## Building and Installation

PGP::Sign uses Module::Build and can be installed using the same process
as any other Module::Build module:

```
    perl Build.PL
    ./Build
    ./Build install
```

You will have to run the last command as root unless you're installing
into a local Perl module tree in your home directory.

## Testing

PGP::Sign comes with a test suite, which you can run after building with:

```
    ./Build test
```

If a test fails, you can run a single test with verbose output via:

```
    ./Build test --test_files <path-to-test>
```

The following additional Perl modules will be used by the test suite if
present:

* Devel::Cover
* Test::MinimumVersion
* Test::Perl::Critic
* Test::Pod
* Test::Pod::Coverage
* Test::Spelling
* Test::Strict
* Test::Synopsis

All are available on CPAN.  Those tests will be skipped if the modules are
not available.

To enable tests that don't detect functionality problems but are used to
sanity-check the release, set the environment variable `RELEASE_TESTING`
to a true value.  To enable tests that may be sensitive to the local
environment or that produce a lot of false positives without uncovering
many problems, set the environment variable `AUTHOR_TESTING` to a true
value.

## Support

The [PGP::Sign web page](https://www.eyrie.org/~eagle/software/pgp-sign/)
will always have the current version of this package, the current
documentation, and pointers to any additional resources.

For bug tracking, use the [issue tracker on
GitHub](https://github.com/rra/pgp-sign/issues).  Please be aware that I
tend to be extremely busy and work projects often take priority.  I'll
save your report and get to it as soon as I can, but it may take me a
couple of months.

## Source Repository

PGP::Sign is maintained using Git.  You can access the current source on
[GitHub](https://github.com/rra/pgp-sign) or by cloning the repository at:

https://git.eyrie.org/git/perl/pgp-sign.git

or [view the repository on the
web](https://git.eyrie.org/?p=perl/pgp-sign.git).

The eyrie.org repository is the canonical one, maintained by the author,
but using GitHub is probably more convenient for most purposes.  Pull
requests are gratefully reviewed and normally accepted.

## License

The PGP::Sign package as a whole is covered by the following copyright
statement and license:

> Copyright 1997-2000, 2002, 2004, 2018, 2020
>     Russ Allbery <rra@cpan.org>
>
> This program is free software; you may redistribute it and/or modify it
> under the same terms as Perl itself.  This means that you may choose
> between the two licenses that Perl is released under: the GNU GPL and the
> Artistic License.  Please see your Perl distribution for the details and
> copies of the licenses.

Some files in this distribution are individually released under different
licenses, all of which are compatible with the above general package
license but which may require preservation of additional notices.  All
required notices, and detailed information about the licensing of each
file, are recorded in the LICENSE file.

Files covered by a license with an assigned SPDX License Identifier
include SPDX-License-Identifier tags to enable automated processing of
license information.  See https://spdx.org/licenses/ for more information.

For any copyright range specified by files in this package as YYYY-ZZZZ,
the range specifies every single year in that closed interval.
