Revisiting discrete logarithms in small/medium characteristic finite fields

Appears in collection : Journées Codage et Cryptographie 2014

In this talk, we present a new algorithm for the computation of discrete logarithms in finite fields of small characteristic. This algorithm combines several previously existing techniques with a few additional ingredients. Among those, the most notable is a new method for generating multiplicative relations with a "systematic side" by composing the polynomial (Xq-X) with homographies. This results in an algorithm of quasi-polynomial complexity for discrete logs in GF(qk) where k is close to q.