The Isogeny Club #5.5 PRISM: PRime degree ISogeny Mechanism

This is the fifth talk of the fifth season of The Isogeny Club, given by Riccardo Invernizzi.
The problem of computing an isogeny of large prime degree from a supersingular elliptic curve of unknown endomorphism ring is assumed to be hard both for classical as well as quantum computers. In this talk, we present an identification protocol and the derived signature whose security reduces to this problem. The challenge consists of a random large prime q, and the response is a degree q isogeny from the public key. The flexibility of this scheme comes at no expenses in terms of efficiency and compactness: signature and public key sizes are comparable to other isogeny based signature schemes, signing is roughly 1.8 times faster than SQIsign2D-West, and verification 1.4 times slower.