International Data Encryption Algorithm

In <a href="/facts/Cryptography/e94PEVau">cryptography</a>, the International Data Encryption Algorithm (IDEA), originally called Improved Proposed Encryption Standard (IPES), is a <a href="/facts/Symmetric-key_algorithm/5zfe0b76">symmetric-key</a> <a href="/facts/Block_cipher/MJywAyfQ">block cipher</a> designed by <a href="/facts/James_Massey/qyfqKnQH">James Massey</a> of <a href="/facts/ETH_Zurich/IxHAFGUU">ETH Zurich</a> and <a href="/facts/Xuejia_Lai/dH2Gk4UG">Xuejia Lai</a> and was first described in 1991. The algorithm was intended as a replacement for the <a href="/facts/Data_Encryption_Standard/STfBjTGb">Data Encryption Standard</a> (DES). IDEA is a minor revision of an earlier <a href="/facts/Cipher/eJnuftYe">cipher</a>, the Proposed Encryption Standard (PES).
The cipher was designed under a research contract with the Hasler Foundation, which became part of Ascom-Tech AG. The cipher was patented in a number of countries but was freely available for non-commercial use. The name "IDEA" is also a <a href="/facts/Trademark/B23H8IS0">trademark</a>. The last <a href="/facts/Patent/LjT2bG3A">patents</a> expired in 2012, and IDEA is now patent-free and thus completely free for all uses.
IDEA was used in <a href="/facts/Pretty_Good_Privacy/4BELG9BW">Pretty Good Privacy</a> (PGP) v2.0 and was incorporated after the original cipher used in v1.0, <a href="/facts/BassOmatic/Tu5Lxrbc">BassOmatic</a>, was found to be insecure. IDEA is an optional algorithm in the <a href="/facts/OpenPGP/4BELG9BW">OpenPGP</a> standard.

International Data Encryption Algorithm open-in-new

International Data Encryption Algorithm