PGP for Mac

From PGP Corporation:

PGP is a tool for keeping your data safe. It contains the following:

• PGP Mail combines encryption and digital signatures to secure your e-mail, attachments, and instant messages. While encryption ensures that a message can't be read by anyone other than its intended recipient. PGP Mail also gives you the flexibility and power to use digital signatures that guarantee the message creator's identity as well as that the message wasn't tampered with, defeating anyone attempting to alter critical communication. Use the various PGP Mail options to automatically encrypt outbound e-mails when the send button is selected.
• PGP Disk allows you to create disks whose contents are encrypted at all times. PGP Disk is particularly critical on laptops, which are increasingly vulnerable to being lost or stolen. By storing data using PGP Disk, users are assured that no unauthorized individual has access to it.
• PGP Keys is the premier public key management utility. It interoperates with many different public key formats algorithms.
• Apple Mail Plugin integrates PGP encryption and signing functionality directly into Apple's Mail application allowing very easy to use message security.
• Entourage Integration also integrates PGP into Microsoft Entourage.
• Mac OS X PGP 8.0 has been rewritten for Mac OS X to take full advantage of the Cocoa environment. It integrates perfectly with the Mac OS X finder via contextual menus, special Dock features, and the Services menu.