So the threat to cryptography is well understood due to work by Peter Shor and others. A symmetric algorithm like AES or others standard crypto processes is cut (of) key-size in half, which is a dramatic reduction. It reduces AES on 128 (bit key) to 64 bits, a DES equivalent. We don’t need it.

So during the AES competition we put in an insurance policy. It was the right thing to do, because it had not yet been built and you have to take care of what you can think of in the long range future. If quantum computing came to be, they said put in a key size 256 (bits). We don’t need it now, its an absurd number, alright, but if quantum computing comes to be, it drops us to 128, a nice healthy number, still quite useable thank you, we can keep going and its no longer a threat.

So it was a marvelous response to quantum computing.

Now for key management purposes, against the RSA and the Diffie-Hellman and stuff, they flat-line under a quantum computer. It’s not just a cut (of) the key size in half.