Re: A poorman's block encryption algorithm



Maaartin wrote:

There's a problem with polynomials you was already told about: They
propagate only towards higher bits (unless you use non-power of two
modulus which is slow). So you can be sure, that a couple of least
significant bits can be found out easily, no matter how many rounds
you do. Starting from them, higher bit can be found, etc. I already
recomennded a remedy, so use it or find another.

Extremely sorry for my poor memory. Could you kindly sketch your remedy
once again or provide a pointer? Concerning predictability of
congruential PRNGs, I previously suggested to use (pseudo-random)
cyclic shift of bits in computer words of the output as a counter-
measure. That could also be done in the present context.

Thanks,

M. K. Shen
.