MRS-AUTH is built on a mathematical forest. The public parameter N is the forest. Every valid representation (A, B) is a tree. Every nested layer adds branches and leaves. The forest contains billions of identical-looking leaves. The key insight is symmetry: an attacker who knows only N, and an attacker who holds a valid chain obtained through coercion, stand in exactly the same position. Every leaf looks identical. The verification function cannot distinguish the real chain from any alibi. This holds without any computational assumption — it is information-theoretic. A secret index designates one specific leaf as authentic. The forest provides unlimited alibis. The secret index provides unforgeability. Together they form a system that is both deniable and secure.
Bilal El Issaoui (Mon,) studied this question.