3a. Doing ECDH (e.g. over Curve25519) and SIDH (or SIKE, the NIST flavor of SIDH) and hashing both together (e.g. with BLAKE2) is a sensible insurance policy ag

3a. Doing ECDH (e.g. over Curve25519) and SIDH (or SIKE, the NIST flavor of SIDH) and hashing both together (e.g. with BLAKE2) is a sensible insurance policy against breakthrough attacks against SIDH.