PGP 5.0 Freeware was recently released by Phil Zimmermann, author of PGP 2.6.x, for distribution within the United States. This new release is a native Windows 95 application (i.e. it does not require a front end and will not work with existing PGP front ends). PGP 5.0 is, like Lock & Key, implemented as a Windows shell extension (right-click to encrypt and decrypt...), and is thus the most similar Windows 95 PGP implementation to Lock & Key.

While PGP 5.0 is very advanced both technically and in terms of usability, its compatibility with earlier versions of PGP is severely limited. PGP 5.0 is designed around new algorithms, and while it will read and write using RSA keys, it does not generate RSA keys. Thus, any key which you generate using PGP 5.0 cannot be used to encrypt or sign messages for existing RSA keyholders.

PGP 5.0 also features e-mail integration with Eudora, MS Exchange and MS Outlook. This should be compared with Lock & Key's integration (send-only) with Eudora and Pegasus Mail, using the KeyChain integrated message editor, which uses the PGP keyring as an address book, supports named groups of keys (encryption/mailing lists), and cleartext and encrypted windows.

In addition, PGP 5.0 does not include many of Lock & Key's features; for example, PGP 5.0 only offers the choice of saving a decrypted file to disk; it cannot be viewed using QuickView, launched, or printed.

Below is an initial attempt to compare PGP 5.0 and Lock & Key feature-for-feature. I will look forward to the reactions of other Lock & Key users who have tried PGP 5.0.