Re: IDEA patent has expired in Europe



On 24/05/2011 15:05, Tom St Denis wrote:
On May 23, 1:00 pm, Francois Grieu<fgr...@xxxxxxxxx> wrote:
BTW, now that IDEA is in the public domain, I which it is made part
of GnuPG (rather than a plugin), for it would very much simplify its
installation.

Why would you use it over AES? Rijndael is based on the SQUARE cipher
which is about 7 years newer than IDEA (1997 vs 1990) but based on
research Daemen was performing in the early 90s. I'd say they've both
stood up to quite a bit of scrutiny.

The only reason I see to use IDEA is compatibility with
something that did.
PGP's RSA legacy keys (which trigger IDEA) are compatible with
almost every version of PGP (not GnuPG) around since at least
PGP 2.6 (with a brief exception that raised so many user
complaints that compatibility with that was promptly
re-introduced); for this reason, and plain inertia, using this
key format, thus IDEA, remained common long after PGP 2.6.3
itself became obsolete.
I occasionally need to decipher some old documents that are
stored enciphered in this way.
I also use an "RSA legacy" key (which triggers IDEA) as a
fall-back when something goes wrong with key format or algorithm
between me (using GPG with IDEA as a plugin) and another party
using an unspecified variant of PGP. So far it always worked.

Francois Grieu
.