You may want to refer to the following sources for background information on cryptography, network security, and SKIP.
Schneier, Bruce, Applied Cryptography: Protocols, Algorithms, and Source Code in C, 2nd Edition, John Wiley & Sons, 1996, ISBN: 0471128457
Chapman, D. Brent and Elizabeth D. Zwicky, Building Internet Firewalls, O'Reilly & Associates, 1995, ASIN: 1565921240
Walker, Kathryn M. and Linda Croswhite Cavanaugh, Computer Security Policies and SunScreen Firewalls, Sun Microsystems Press, Prentice Hall, 1998, ISBN 0130960150
Cheswick, William R. and Steve Bellovin, Firewalls and Internet Security: Repelling the Wily Hacker, 1st edition, Addison-Wesley, 1994, ISBN 201633574
Black, Uyless D., Internet Security Protocols: Protecting IP Traffic, 1st Edition, Prentice Hall, 2000, ISBN: 0130142492
Comer, Douglas E., Internetworking with TCP/IP, 3rd Edition, Volume 1, Prentice Hall, 1995, ISBN 0132169878
Doraswamy, Naganand and Dan Harkins, Ipsec: The New Security Standard for the Internet, Intranets, and Virtual Private Networks, 1st Edition, Prentice Hall, 1999, ISBN: 0130118982
Stallings, William, Network and Internetwork Security: Principles and Practice, Inst Elect, 1994, Product#: 0780311078
Kaufman, Charlie and Radia Perlman, Mike Speciner, Network Security: Private Communication in a Public World, 1st Edition, Prentice Hall, 1995, ISBN: 0130614661
Garfinkel, Simson and Gene Spafford, Practical Unix and Internet Security, 2nd Edition, O'Reilly & Associates, 1996, ISBN: 1565921488
Farrow, Rik, UNIX System Security: How to Protect Your Data and Prevent Intruders, Addison-Wesley, 1990, ISBN: 0201570300
Kaufman, Elizabeth and Andrew Neuman, Implementing IPSec: Strategies for Making Network and VPN Security Work, Wiley, John & Sons, Incorporated, 1999
Sun Software and Networking Security: http://www.sun.com/security/
A public SunScreen discussion forum at Sun's Support Forum site is also available. See http://supportforum.sun.com/cgi-bin/WebX.cgi?/security.sunscreen.