Wednesday, December 3, 2025 10:30 am
-
11:30 am
EST (GMT -05:00)
Title:PRISM: Simple And Compact Identification and Signatures From Large Prime Degree Isogenies
| Speaker | Nic Swanson |
| Affiliation | University of Waterloo |
| Location | MC 5479 |
Abstract: 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 work, we first build a two-round identification protocol whose security reduces to this problem. The challenge consists of a random large prime q and the prover simply replies with an efficient representation of an isogeny of degree q from its public key.
Using the hash-and-sign paradigm, we then derive a signature scheme with a very simple and flexible signing procedure and prove its security in the standard model.
Our optimized C implementation of the signature scheme shows that signing is roughly 1.8× faster than all SQIsign variants, whereas verification is 1.4× times slower. The sizes of the public key and signature are comparable to existing schemes.