Cryptography Reference
In-Depth Information
Table 5.1
Patent protection of IDEA; source: company brochure (as of March 5, 1996)
Country
Patent number
Filed on
Granted on
Expiry
Europe:
0482154
5/16/1991
6/30/1993
5/16/2011
Austria,
France,
Germany,
Great Britain,
Italy,
Netherlands,
Sweden,
Switzerland,
Spain,
USA
5'214'703
5/16/1991
5/25/1993
5/25/2010
Japan
508119/1991
5/16/1991
pending
often that I will describe the legal issues before discussing the algorithm itself.
Table 5.1 shows the details.
The current licensing terms and conditions can be obtained directly from Ascom
Systec AG (
www.ascom.com
).
At the beginning of 1996, the license fees ranged between 2 and 15 dollars per
user, where not all employees in companies are counted as users, depending
on their type of classification.
As a sideline, the fact that algorithms cannot be patented in Germany or else-
where doesn't matter: IDEA is patented in Switzerland, and this patent is
effective in other countries, too.
Use of the algorithm is free for non-commercial purposes, but a copyright
notice has to be included in the corresponding software, and the developer
should contact Ascom prior to publication.
5.3.2 The IDEA Method
After this legal stuff, let's return to cryptology:
•
IDEA works with 64-bit blocks and uses a 128-bit key. This key is used
to create 52 subkeys of 16 bits each as follows.
The key is first decomposed into eight subkeys of 16 bits each. These
are the first eight subkeys.
