From: patrick@Verity.COM (Patrick Horgan)
Date: Fri, 22 Sep 95 08:15:47 PDT
To: cwe@Csli.Stanford.EDU
Subject: Re: Exchange random numbers (was: Re: netscape's response)
Message-ID: <9509221511.AA19305@cantina.verity.com>
MIME-Version: 1.0
Content-Type: text/plain


> 
> This isn't a problem as I see it, he'll only know what bits he
> flipped, not the actual state.

Wouldn't even know that if you permuted it.  You _could_ use a fixed
permutation, or you could use input information from another source
to select the permutation.  Even something as simple as taking 5 bits
from one source and using another source mod(random seed length) to
decide where to xor it into the random seed.  (Rotating back to the 
front if needed, or you could let the bits fall off the end.) And if
all you ever give out to randomness partners is the result of a good
hash there's no way they could ever determine anything from it, or
determine what effect their contribution had.  Shoot, they wouldn't
know if their contribution went into the seed, or merely affected
how someone elses contribution went into the seed.

Patrick

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