IDEA (was: Re: Decryption problem)

Johan Wevers
Wed, 15 Sep 1999 17:50:51 +0200 (MET DST)

Robert Fendt wrote:

> The use by a "private individual" for "non-commercial purposes" is, by my
> understanding, free.
Well, I use it mostly in communications I don't want the Scientology cult to read, which are non-commercial.
> Nevertheless, this stands in direct contrast to the GPL;
> so, IDEA cannot be incorporated into GnuPG.
Not directly that is.
> This brings me to an interesting question: one of the two algorithms'
> patents (RSA and IDEA) ends somewhere in 2001,
The RSA patent ends on September 20, 2000 (according to thr rsc.c gpg module). I don't when the IDEA patent ends.
> And: how specific are these patents anyway? Would it be possible to create
> a different cipher based on the same mathematical principle (and therefore
> with comparable qualities) without breaking a patent? After all, RSA is
> faster than DH, and IDEA has undergone extensive analysis.
That would require a thourough analyses of those tweaked algorithms by cryptographers. And because IDEA and RSA have survived this without having shown any serious weaknesses they are trusted algorithms. But a small change can completely destroy their security. -- ir. J.C.A. Wevers // Physics and science fiction site: // Finger for my PGP public key. PGP-KeyID: 0xD42F80B1