Stephen,

Check out 1crypt (onecrypt) from:

http://www.atma-software.com/1crypt/

This is a $20, standalone, 82K DLL that does not need to be registered. It provides AES 256 encryption for files and strings. Simple interface. Good support from vendor. Note: The string encryption returns encrypted strings in a hex string format, so for storage you would need to double your field widths or convert these hex strings to a binary string.

Malcolm