# Topal — Features

Copyright © 2001–2024 Phillip J. Brooke

Topal is a ‘glue’ program that links GnuPG and Pine/Alpine/Re-Alpine. It offers facilities to encrypt, decrypt, sign and verify emails, including inline OpenPGP, MIME/OpenPGP and S/MIME. It can also be used directly from the command-line.

- Multiple inline PGP blocks can be processed in display filters.
- Decryption and verification output can be cached to reduce the number of times a passphrase is entered. This also helps when secret keys aren't always available, at the expense of storing decrypted output.
- MIME/OpenPGP (RFC2015/RFC3156) multipart messages can be sent and received. Depending on configuration, this might involve procmail, using `sendmail-path` or patching Alpine.
- The deprecated application/pgp content-type can be sent and received.
- S/MIME messages can be sent and received if `gpgsm` is available. (`openssl` is also used in some circumstances, but `gpgsm` is still required.)
- Topal can be used as Alpine's `sendmail-path` command.
- Topal has a remote sending mode (a server and a means of accessing the server) for reading email on a distant computer via SSH with secret keys on the local computer.
- A range of mechanisms for selecting keys for both self and recipients.
- There is a high level of configurability (although the configuration interface does not expose all of it; you might have to edit `.topal/config`).

See the documentation in `topal.pdf` for further details.