Our website provided a free download of Ciphire Mail 1.2 for Mac. The software lies within Communication Tools, more precisely E-mail.
From the developer:
Ciphire Mail is an email encryption tool. It works in conjunction with your existing email client. Ciphire Mail operates seamlessly in the background and does not interfere with normal emailing routines. It encrypts and decrypts email messages, and can digitally sign each message to provide authentication and guard against identity theft. Ciphire Mail is the first out-of-the box solution to match power with ease of use.
You may want to check out more software for Mac, such as Mail.Ru Agent, Mail Backup X or Postage Calculator for Royal Mail, which might be similar to Ciphire Mail.
Instant messaging
E-mail Tools