Kremlin Encrypt 3.0

[ Via Apple.com ] Provides a cross-platform security suite for Mac and PC. It builds a wall around your data, protecting your sensitive information from snooping intruders.
Easily encrypt-decrypt your files in drag-and-drop manner with Kremlin Encrypt and Kremlin Decrypt tools.

Encrypted files can be transferred seamlessly between Mac and PC environments. In addition to a portable file format, now licensing and registration is also fully portable across platforms.
You can also schedule the Kremlin to automatically encrypt the files when you log off your computer and decrypt Requirements
PPC, Mac OS X 10.1 or later