This e-mail encryption software uses 8192-bit RSA public key encryption and a secure 384-bit cipher, incorporating the AES candidate Twofish algorithm; SecExMail features PGP-style e-mail keys, but without the dependence on e-mail-software-specific plug-ins.

The software runs unobtrusively as a relay agent in the system tray on your desktop and actively filters messages between your e-mail client and your mail server, encrypting and decrypting mail to and from known users in real-time.

SecExMail is certified to operate with all SMTP POP3 e-mail clients, including Microsoft Outlook, Netscape Mail, IncrediMail, Pegasus, The BAT, Eudora, and Calypso.
SecExMail protects against cryptanalysis at the protocol level: e-mail subject lines are encrypted. All attachments to secure messages are autoencrypted, including their file names and MIME type information. SecExMail is built on the Open SSL secure socket layer library.

Now includes automatic key exchange and powerful html filtering to protect from malicious email. Personal Edition, including support can be purchased for $4.95 using PayPal or Credit Card. Commercial, Lindows and Linux versions available.