Papers We Love Conf 2022

September 22, 2022 / St. Louis, Missouri

Deirdre Connolly

Zcash Foundation

photo of Deirdre Connolly

A Requiem for SIDH: Efficient algorithms for supersingular isogeny Diffie-Hellman

Isogeny-based cryptography went from a curiosity to a serious post-quantum contender arguably because of this paper from Costello, Longa, and Naehrig from Microsoft Research. But excellent applied cryptography did not save SIDH from the design choice that made it useful, and doomed it. We will explore isogeny-based cryptography, how we got SIDH, how this paper was a game-changer for isogeny-based cryptography, how SIDH died, and what isogeny-based cryptosystems may pick up the baton for the future.


Deirdre Connolly does cryptography at the Zcash Foundation. She works on secure implementations of cryptographic software with an eye on privacy applications, misuse-resistance, and quantum adversaries. She obtained her BS from MIT in 2008. She also co-hosts a podcast.