2018.04.30 06:25:45 (990809407427661824) from Daniel J. Bernstein, replying to "Frédéric Grosshans (@fgrosshans)" (988704846139228160):
And how do you define "communication channels" without making ad-hoc references to QKD? How does your definition exclude a trivially "secure" solution where A&B send random garbage through the "communication channels" and, separately from that, have a pre-shared secret key?
2018.04.21 13:00:52 (987647350540730369) from Daniel J. Bernstein, replying to "Frédéric Grosshans (@fgrosshans)" (987013879338340353):
So you think that "absolute security" of an exchanged key means that it's safe against all attacks, but crossing out the word "absolute" means that it's referring only to attacks intercepting the photons in the particular key-exchange protocol you have in mind?
2018.04.22 13:40:01 (988019591958974465) from "Frédéric Grosshans (@fgrosshans)":
By standard QKD model, I mean the adversary: - has access to all classical communications and unlimited computing power - can perform arbitrary interaction with the quantum pulses The apparatuses are supposed to be well modelled physically and well shielded.
2018.04.23 02:00:11 (988205858587897856) from Daniel J. Bernstein, replying to "Frédéric Grosshans (@fgrosshans)" (988019591958974465):
Are you capable of defining your concept of security for exchanged keys _without_ making ad-hoc references to the particular structure of QKD as part of the definition?
2018.04.24 11:02:59 (988704846139228160) from "Frédéric Grosshans (@fgrosshans)":
Let me try : A key exchange is a protocol where A&B establish a secret key through interaction via communication channels. “Secret” means ε-close to uniform random for an adversary having access to said communication channels.