IDEA (International Data Encryption Algorithm), formerly known as IPES
(Improved Proposed Encryption Standard).

Algorithm developed by Xuejia Lai and James L. Massey, of ETH  Zurich.
This   implementation  modified  and  derived  from  original  C  code
developed by Xuejia Lai.

Extensively optimized and restructured by Colin Plumb.

The IDEA algorithm was developed by Xuejia Lai and James L. Massey, of
ETH  Zurich.   The  implementation  used  in  Netfone was modified and
derived from original C code developed by Xuejia Lai and optimized for
speed  by  Colin Plumb <colin@nsq.gts.org>.  The IDEA[tm] block cipher
is  patented  by  Ascom-Tech  AG.   The   Swiss   patent   number   is
PCT/CH91/00117, the European patent number is EP 0 482 154 B1, and the
U.S. patent  number  is  US005214703.   IDEA[tm]  is  a  trademark  of
Ascom-Tech AG. There is no license fee required for noncommercial use.
Commercial users may obtain licensing details from Dr.  Dieter Profos,
Ascom-Tech   AG,  Solothurn  Lab,  Postfach  151,  CH-4502  Solothurn,
Switzerland, Tel +41 65 242 885, Fax +41 65 235 761.

For  further information on the IDEA cipher, see: Xuejia Lai.  "On the
Design and Security of  Block  Ciphers",  ETH  Series  on  Information
Processing  (ed.  J.L. Massey) Vol 1.  Hartung-Gorre Verlag, Konstanz,
Switzerland, 1992.  ISBN 3-89191-573-X.