If you are looking for generic J2ME crypto packages, check out my earlier article here: Data security in mobile Java applications http://www.javaworld.com/javaworld/jw-12-2002/jw-1220-wireless.html Bouncy Castle is nice. But as I mentioned in the article, its public algorithm key performance is poor and does not have good key serialization support. [ March 13, 2003: Message edited by: Michael Yuan ]