Assume the following simplified protocol:
- seed = curve25519SharedKey(theirPublicKey, myPrivateKey)
- sharedKey = scrypt(seed, salt, sufficientlyHardWorkFactors...)
- cipherText = aes256(sharedKey, clearText)
Does using a slow-hash on the output of an asymmetric key-exchange offer any more protection in a quantum-computing era? I know that quantum computing is supposed to make breaking diffie-hellman easy... what I don't know is exactly how easy. Is the algorithm (greatly) diminished, or completely broken?