SecExMail SOHO

Free email encryption utility for personal and corporate use. SecExMail works as a proxy, which means it configures itself to be between your email client and your email server. It automatically encrypts and decrypts email as it's sent or received. Features PGP-style e-mail keys, but without the dependence on e-mail-software-specific plug-ins.
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.

Требования:

Windows 98, ME, NT, 2000, XP, Vista, 7