Example
of a difficult underlying problem:

Discrete Logarithm on (Z/pZ)*, p prime.

Discrete Logarithm on (Z/pZ)*, p prime.

(**Z**/p**Z**)* is abstractly isomorphic to **Z**/(p-1)**Z**.

For example, p=19: (**Z**/19**Z**)* ' **Z**/18**Z** is generated by powers of 2.

(Z/19Z)*

Z/18Z

Powers of 2

This sequence appears to be fairly random

k ! 2k