Inside AppleTalk (Addison Wesley, ISBN #0-201-19257-8), pages 13-28 to 13-30,
discusses user authentication methods. Pages 13-29 and 13-30 discuss the AFP
random exchange authentication method, which uses the NBS DES (National
Institute of Standards and Technology Data Encryption Standard) algorithm.
For more specific answers about this algorithm -- or to get the algorithim
itself -- contact the National Institute of Standards and Technology.
We also found a DES encryption program written in C starting on page 262 of a
book called "UNIX System Security". The book, written by Patrick H. Wood and
Stephen G. Kochan, is published by Hayden Books (ISBN #0-8104-6267-2).
For more information, search under: "National Institute of Standards and
Technology"