These scripts are modified versions of those enclosed in the MacPGP 2.6.2 package.
They also include small snippets and inspiration via Robert's PGP scripts.
They are much improved in my opinion because:
1) They are more consistent in syntax and easier to read.
2) They don't do strange things like save decrypted text as a script property?!?
3) They don't require scripting additions (although it helps).
4) And finally they are compatible with Eudora Pro v2.1.3, or more precisely they avoid a gigantic bug in this particular version.
The best way to run these scripts is with OSA Menu 1.0.2 or higher and the scripting additions they like to have handy are Jon's Commands 1.3.6 or higher and Menu Events 1.1.2 or higher.
To avoid the bug in Eudora Pro v2.1.3 I had to work on the message in question while the window for it was closed. This is not easy because you can always address the top open window as message 0 but once it's closed you need a more specific reference. Therefore before encryption the selected message is closed and moved to the end of the Out mailbox (or copied to it if it was not already in the Out mailbox). Also before decryption the message is moved to the end of the In mailbox (even if it was already somewhere else). I don't imagine that this is too much of a problem considering that most of the time moving will consist of putting the message right back where it was. But, if anyone has a better idea I'd gladly listen...
You can open these scripts in Script Editor and modify them to your heart's content (and I encourage that you do) as they still fall under the GNU General Public License of the original scripts.
I don't really intend to maintain these scripts, I just thought I'd put them out in order to save some people the trouble I went throught to make them.