[Cryptography] Yet another dumb crypto system
Viktor Dukhovni
cryptography at dukhovni.org
Wed Sep 23 22:58:53 EDT 2015
On Wed, Sep 23, 2015 at 02:09:52PM -0700, Bill Cox wrote:
> Enjoy breaking this probably very old crypto system that was probably
> broken decades ago :)
Don't waste time on this.
> Instead, I'm using a couple of simple "reduction
> rules". The two rules are:
>
> x^2 => x + 3
> y^2 => 2y
The y^2 = 2y reduction rule is not so good. This means that
y*(y-2) = y^2 - 2y = 0
which makes the set of non-zero polynomials not a group under
multiplication.
To avoid such problems you'd want x and y to be roots of distinct
irreducible quadratic polynomials. This then turns your system
into a degree 4 Galois extension of F_p.
DLP for Galois extensions is not a new problem.
--
Viktor.
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