From: jim bell <jimbell@pacifier.com>
Date: Thu, 1 Feb 1996 13:47:36 +0800
To: Peter Monta <cypherpunks@toad.com
Subject: Re: Crypto-smart-card startup Inside Technologies
Message-ID: <m0thqvv-00092XC@pacifier.com>
MIME-Version: 1.0
Content-Type: text/plain


At 12:30 AM 1/31/96 -0800, Peter Monta wrote:
>There's an article in the January 29 _EE Times_ about a French
>cryptographic-smart-card startup called Inside Technologies.
>Tidbits:
>
>  ..."In public-key cryptography, 512-bit keys are typical and
>  already vulnerable.  So we are looking at 640-bit-long keys
>  supported by a scalable design."


This kind of thing disgusts me.  We already know 512-bit keys are weak.  As
I recall, I was told that 512 bit keys could be cracked in 20,000
MIPS-years.  If the ballpark formula holds that adding 10 bits doubles the
security, that merely means that 640 bits is 2**(128/10) or 8000 times
strong.  While obviously better than 512, it is not ENOUGH better to make me
confident that this is a long-term secure length.  768 or 1024 bits should
be considered the minimum.  A deliberate design of 640 bits makes it look
like it's intended to be crackable in 5-10 years, much as DES was suspected
of a similar design decision in limiting its keylength to 56 bits.