Diffie-Hellman with Galois field

Question

I Google around and can't find any page mentioning Diffie-Hellman with Galois field $GF(p^n)$ with $n>1$.

• Is there a reason for this?
• For example, wouldn't Diffie-Hellman with $GF(2^n)$ be desirable for computation?

Answer 1

The security of the Diffie-Hellman protocol relies on the Decisional Diffie-Hellman assumption, which is a stronger assumption than the Discrete-Logarithm Problem (DLP). In an earlier line of works, heuristic quasi-polynomial algorithms were shown for fields with small characterstic [J,BGJT,GKZ]. A proof (for expected run-time) was recently given by Wesolowski and Kleinjung [WK]. In particular, it was shown that DLP in $\mathbf{F}_{p^n}^\times$ can be solved in (expected) time $(pn)^{O(\log{n})}$. In light of these attacks, the Diffie-Hellman protocol should be avoided in fields of small characteristic.

[J] Joux, A new index calculus algorithm with complexity L(1/4+o(1)) in very small characteristic

[BGJT] Barbulescu et al., A Heuristic Quasi-Polynomial Algorithm for Discrete Logarithm in Finite Fields of Small Characteristic

[GKZ] Granger, Kleinjung and Zumbrägel, On the discrete logarithm problem infinite fields of fixed characteristic

[WK] Wesolowski and Kleinjung Discrete logarithms in quasi-polynomial time in finite fields of fixed characteristic