International Data Encryption Algorithm

In cryptography, the International Data Encryption Algorithm, or IDEA, originally called the Improved Proposed Encryption Standard, is a symmetric-key block cipher designed by James Massey of ETH Zurich and Xuejia Lai and first described in 1991, intended as a replacement for the Data Encryption Standard. IDEA is a minor revision of an earlier cipher, the Proposed Encryption Standard, and was developed under a research contract with the Hasler Foundation, later part of Ascom-Tech AG. It was patented in a number of countries but freely available for non-commercial use, with the last patents expiring in 2012, after which it became free for all uses. IDEA was used in Pretty Good Privacy version 2.0, replacing the original BassOmatic cipher used in version 1.0 after BassOmatic was found to be insecure, and remains an optional algorithm in the OpenPGP standard.