3 ms·
From my research so far it looks like SIDH is the most promising candidate to upgrade existing protocols (relatively congruent to ECDH; "small" key sizes). For
by blattimwind 9y ago
From my research so far it looks like SIDH is the most promising candidate to upgrade existing protocols (relatively congruent to ECDH; "small" key sizes).
For proprietary protocols the "newiness" of pq-crypto doesn't seem to be a big problem per se, just use curve hardening (kdf(ECDH || pq-kex)) in case the pq-crypto is broken (either due to implementation defects or cryptanalysis).
- dsacco 9y agoIt depends on the application. SIDH is attractive because it doesn’t throw out decades of elliptic curve mathematics because of the spectre of quantum computers. The mathematics is a bit more familiar if you squint at it, though working with isogenies themselves is still very different from normal elliptic curve cryptography. But more importantly, a codebase that implements elliptic curve arithmetic can port much of that functionality to implement SIDH. And yes - SIDH is also attractive because of the small key sizes. But it’s also significantly slower than lattice-based key exchange using something like Learning With Errors (LWE). In practice the decision comes down to time versus space constraints: if your application is space-poor and time-rich, SIDH is a good proposal for key exchange. This looks especially nice in the context of IoT devices. But if your application is space-rich and time-poor, SIDH looks less attractive in favor of other options.