I've taken the liberty of Cc:ing the list on a reply to individual email,
so I've anonymised the sender.
At 17:00 1/01/99 -0800, someone wrote:
>Greg Rose wrote:
>> It was Phil Karn, I've seen the form. He was trying to export a VPN box
>> of some kind to the QUALCOMM office in Singapore. They did allow IDEA,
>> eventually. Phil thinks that allowing a 128-bit algorithm but not 112-bit
>> 3des was some sort of mind game.
>>
>
>I thought IDEA has a large number of weak/semi-weak keys?
>
>Without knowing better I'd think the usable key space is smaller than
>3DES? (I haven't worked out the math)
I've forgotten the actual number, but the vaguely weak keys are something
of the order of 2^-72 of the actual keyspace. When you think about it this
way, the chance of accidentally getting a weak key is *much* less than the
chance of guessing a DES key first try. Expressed in terms of the supposed
strength of an IDEA key, the IDEA keyspace is about 2^127.99998 or
something; still much larger than the 2^112 of two-key 3des. Yes, the
number of weak IDEA keys is numerically large. Proportionally, it is tiny.
(The word "known" should be assumed to appear in appropriate places above.)
regards,
Greg.
Greg Rose INTERNET: [EMAIL PROTECTED]
Qualcomm Australia VOICE: +61-2-9181-4851 FAX: +61-2-9181-5470
Suite 410, Birkenhead Point, http://people.qualcomm.com/ggr/
Drummoyne NSW 2047 232B EC8F 44C6 C853 D68F E107 E6BF CD2F 1081 A37C
