- Checking signatures of received emails
- Decrypting received emails
- Sending signed and/or encrypted emails
- Creating new key pairs easily
- Optionally, caching your passphrase or using gpg-agent.
Although deprecated, the PGP/Inline method of signing or encrypting emails is still available, because some mail user agents like Outlook do not handle PGP/Mime well, more than ten years after creation of this standard.
GnuPG and GPGME are required, http://www.gnupg.org/