Secure Addressbook is based on the JavaScript implementation of Wheeler & Needham's Block TEA (Tiny Encryption Algorithm) by Chris Veness. It allows maintaining secure records even the on shared hosting server, as data en/decrypted at browser only.
The Tiny Encryption Algorithm (TEA) was developed by David Wheeler and Roger Needham at the Computer Laboratory of Cambridge University. The variant used was developed by David Wagner. TEACrypt 80x86 is the porting of this algorithm to the 80x86 platform