Cryptanalysis of the Legendre PRF - Implementation

This repository contains an implementation of the attack from the paper

Cryptanalysis of the Legendre PRF and Generalizations

by Ward Beullens, Tim Beyne, Aleksei Udovenko, and Giuseppe Vitto.

The code can be used to break Challenge 2 of the Legendre PRF Bounties in under 1500 CPU-hours. For more details, please refer to the paper.

The code can be run with the following command:

$ make threads=24 target=P74

• threads argument defines the amount of threads to be used in the second step of the attack;
• target argument can be one of P40, P64, P74, P84.

It requires a C++ compiler to be installed. Clang++ is recommended. Furthermore, libgmp must be installed.