RC-4 is the standard encrption logic, it has been while and pretty stable.

Here is the link for using RC4 encrption.

http://www.databasejournal.com/img/RC4_enhanced.sql

Cryptology is a huge subject.

Here is the link for how to have a secure system

http://www-theory.dcs.st-and.ac.uk/~...tml/node4.html