Welome to the Internet, here's your private key

[Scott Guthery]

An 8-bit 1/2 MIP smart card can generate 1024 bit RSA key
pair in about 20 seconds and 512 bit key pair in less
than 5 seconds.

Since this isn't typically done in the checkout lane 
this is certainly an acceptable time/security trade-off 
by many lights.  A device that can't generate a key pair
probably has other more compelling shortcomings as a
security token.

Cheers, Scott  

-----Original Message-----
From: Bill Frantz [mailto:frantz at pwpconsult.com]
Sent: Monday, February 04, 2002 3:42 PM
To: Bill Stewart; cryptography at wasabisystems.com
Subject: RE: Welome to the Internet, here's your private key


At 10:20 AM -0800 2/4/02, Bill Stewart wrote:
>There are special cases where the user's machine doesn't have
>the CPU horsepower to generate a key - PCs are fine,
>but perhaps Palm Pilots and similar handhelds are too slow
>(though a typical slow 33MHz 68000 or Dragonball is faster
>than the 8086/80286 MSDOS machines that PGP originally ran on.)
>Cash machines may be too slow, but they normally run symmetric crypto.
>A smartcard-only system probably _is_ too limited to generate keys,
>but that's the only realistic case I see.

It may depend on the public key system you are using.  Where you have to
search for numbers which have certain mathematical properties (like with
RSA), then you can indeed use a bunch of CPU.  For systems like DSA, where
the private key is in essence a random number, there is not searching, and
key generation is a lot faster.

Cheers - Bill


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