[RC5] d.net progress

Keith Jones keith at streamdata.com
Fri Nov 21 12:00:53 EST 1997


gindrup at okway.okstate.edu wrote:

>      But, remember, a *real* effort would use the information that the
>      first several bytes of the decrypted message are "The unknown message
>      is: ", the next byte is capitalized ASCII and all the remaining bytes
>      are printable ASCII characters followed by some (possibly empty)
>      sequence of NULLs (padding).
>      We aren't even remotely using all this information.  We're attacking
>      by pure brute-force.

I was under the impression that we *were* using this information.  I certainly was
when I whipped together an RC5-40 cracker a couple of weeks ago (which was woefully
inadequate to the task, if you must know ... one PPro 200 just doesn't cut it for
breaking RC5-40 though my program was not as optimized as it could be).

My impression is that the RSA contest is a known plaintext, known ciphertext
attack.

Keith W. Jones -- keith at streamdata.com

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