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The following archive was created by hippie-mail 7.98617-22 on Sat Apr 10 1999 - 01:15:22
Mok-Kong Shen (mok-kong.shen@stud.uni-muenchen.de)
Wed, 21 Oct 1998 11:15:03 +0100
Niels Möller wrote:
>
> In the eurocrypt-98 rump session, Adi Shamir proposed the following
> construction:
>
> Given some pseudorandom function F (iirc, Shamir used a hash function,
> but the same should apply to a block cipher with a fixed (secret)
> key), construct a sequence by iterating
>
> x_0 = some secret seed value
> x_{i+1} = F(x_i) + i (where + is addition or bitwise xor).
>
> This simple construction guarantees that there are no short cycles,
> because if i != j, then x_i = x_j implies x_{i+1} != x_{j+1}. The
> sequence can't repeat until the counter wraps around.
I haven't yet understood the stuff. The above does not seem to
exclude the possibility of, say, x_{i+2} = x_{j+2}.
M. K. Shen
The following archive was created by hippie-mail 7.98617-22 on Sat Apr 10 1999 - 01:15:22