Wouter Castryck and Thomas Decru recently broke SIDH.
From the abstract:
We present an efficient key recovery attack on the Supersingular Isogeny Diffie-Hellman protocol (SIDH), based on a "glue-and-split" theorem due to Kani.
The referenced Kani work is:
Ernst Kani, The number of curves of genus two with elliptic differentials, Journal für die reine und angewandte Mathematik 485, pp. 93–121 (1997), available at https://www.mast.queensu.ca/~kani/papers/numgenl.pdf
I have two questions:
Does it mean the end of isogeny-based cryptography?
Why so late? 1997 to 2022?