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The following archive was created by hippie-mail 7.98617-22 on Fri Aug 21 1998 - 17:15:57 ADT
Bill Frantz (frantz@netcom.com)
Wed, 11 Mar 1998 20:04:56 -0800
At 9:44 AM -0800 3/11/98, Bill Stewart wrote:
>>For DES, key setup time can be traded for memory. My guess would be
>>that key setup using 32K tables can be as fast as an encryption.
>
>There are several different cases
>- individual messages, such as mail or SSL
>- mixed data streams, with separate keys for each stream
>- key cracking
>
>For key cracking, Peter Trei's work lets you generate one key schedule
>from another with near-zero effort if you search the keys in the right order.
>
>For mixed data streams, you can manage caches of key schedules to avoid
>recalculating the schedule each time you switch input streams,
>though managing caches of anything is an art, and the dividing line
>between mixed data streams and lots of individual messages can be fuzzy.
Using the Cryptix Java library, caching the key schedules falls our
naturally. As part of creating an instance of a DES encrypter, it converts
the key to an "efficient" internal format. You only need to associate an
instance of DES with the communication channel instance and it all falls
out naturally.
Thanks Eric for your performance tables. It is nice getting real-world
measurement instead of theoretical guesses. Can you easily come up with
the storage costs for the internal optimized state for your cyphers?
Being able to devote a large amount of storage to cached state is where
software crypto beats out dedicated hardware.
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Bill Frantz | If hate must be my prison | Periwinkle -- Consulting
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frantz@netcom.com | the key. - Phil Ochs | Los Gatos, CA 95032, USA
The following archive was created by hippie-mail 7.98617-22 on Fri Aug 21 1998 - 17:15:57 ADT