Craig Costello
Microsoft Research cryptographer who made elliptic curves and isogenies fast enough to use – and co-designed SIKE.
With Patrick Longa, Costello introduced the FourQ curve in 2015, which combines several endomorphisms to do scalar multiplication up to roughly twice as fast as Curve25519. It never saw wide protocol adoption, but it showed how much performance was still left in well-chosen curves.
The following year Costello, Longa and Michael Naehrig published fast algorithms and a library for SIDH, which made isogeny-based key exchange something you could actually benchmark. He went on to co-author SIKE, and in 2022 watched it fall to about an hour of computation. An unusually clear example of engineering that was excellent and still sat on the wrong foundation.