This paper presents a practical implementation of field level encryption in enterprise database systems, based on research and practical experience from many years of commercial use of cryptography in database security. column-level database encryption is the only solution that is capable of protecting against external and internal threats, and at the same time meeting all regulatory requirements. The key concepts of security dictionary, type transparent cryptography and propose solutions on how to transparently store and search encrypted database fields are used.
http://www.net-security.org/article.php?id=715