Crypt::OpenPGP is a pure-Perl implementation of the OpenPGP standard[1].
In addition to support for the standard itself, Crypt::OpenPGP claims
compatibility with many other PGP implementations, both those that
support the standard and those that preceded it.

Crypt::OpenPGP provides signing/verification, encryption/decryption,
keyring management, and key-pair generation; in short it should provide
you with everything you need to PGP-enable yourself. Alternatively it can
be used as part of a larger system; for example, perhaps you have a
web-form-to-email generator written in Perl, and you'd like to encrypt
outgoing messages, because they contain sensitive information.
Crypt::OpenPGP can be plugged into such a scenario, given your public
key, and told to encrypt all messages; they will then be readable only by
you.

This module currently supports RSA and DSA for digital signatures, and
RSA and ElGamal for encryption/decryption. It supports the symmetric
ciphers 3DES, Blowfish, IDEA, Twofish, and Rijndael (AES). Rijndael is
supported for key sizes of 128, 192, and 256 bits. Crypt::OpenPGP
supports the digest algorithms MD5, SHA-1, and RIPE-MD/160. And it
supports ZIP and Zlib compression.