Re: DES & IBM's patents

Kriston J. Rehberg (kriston@ibm.net)
Mon, 20 Jul 1998 18:19:17 -0400

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I was poking around on the www.patents.ibm.com server and I'm curious as
to which patents you are referring.

Kris

Bob Baldwin wrote:
>
> On Mon, 20 Jul 1998 14:45:22-0400, Perry E. Metzger wrote:
> >DES has been routinely used in weird new modes, and IBM never
> >attempted to enforce the patent on it under any circumstances.
> >They accepted that DES was no longer something they should
> >expect to profit from.
>
> Actually, IBM has enforced its patents for digest functions
> based on DES (or any other block cipher) called MDC-2
> and MDC-4. It also has a patent on using DES to create
> a 40-bit keyspace version called CDMF. Both of these
> "weird new modes" for DES are patented and IBM does in
> fact enforce them.
>
> --Bob Baldwin
> RSA Data Security

-- 
Kriston J. Rehberg
http://kriston.net/
AOL: Kriston                                   endeavor to persevere

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