The cr.yp.to microblog: 2018.02.04 01:08:16

2018.02.04 01:08:16 (959941641758019584) from Daniel J. Bernstein, replying to "Paulo Barreto (@pbarreto)" (959887273738162176):

The claimed simulation (of Simon's method on a non-quantum computer) cheats by asking the user to provide the period as input. For an earlier and more general cheat see "trapdoor simulation" in https://cr.yp.to/talks.html#2015.04.03. Useful for verification but not for actual computations.

Context

2018.02.03 10:46:06 (959724666968526849) from "Daniel Loebenberger (@dloebenberger)", replying to "Paulo Barreto (@pbarreto)" (959671920349265920):

I will believe this once someone shows me an actual running attack!

2018.02.03 11:58:32 (959742896164483072) from "Niklas Johansson (@Niklas_Skans)", replying to "Daniel Loebenberger (@dloebenberger)" (959724666968526849):

Unfortunately I don't think it is that simple. The attacks by Kaplan et al. (and earlier results by Kuwakado and Morii http://ieeexplore.ieee.org/document/5513654/, http://ieeexplore.ieee.org/document/6400943/) only works if the protocols are built into a physical system (quantum)...

2018.02.03 19:25:20 (959855338378944522) from "Daniel Loebenberger (@dloebenberger)", replying to "Niklas Johansson (@Niklas_Skans)" (959742896164483072):

But then it cannot be considered a classical break, can it?

2018.02.03 21:32:14 (959887273738162176) from "Paulo Barreto (@pbarreto)", replying to "Daniel Loebenberger (@dloebenberger)" (959855338378944522):

The original attack by Kaplan et al. is quantum and depends on the (so often called "useless") Simon algorithm. The point here is in which conditions it can be de-quantized, since Simon itself can be efficiently simulated classically.