On 8/22/14, 5:50 PM, Andy Isaacson wrote: > It seems a little silly to me too, but I'm encouraged to see new > innovations in end user security systems, especially when they're not > trying to do something fundamentally impossible and seem to have a > reasonable grasp of what's required.
Did anyone else get the sense that their "pairing code" is a truncated hash of the session key, and thus vulnerable to the MitM forcing the two session keys to achieve a partial collision of the codes? Sounds like a job for SAS[1] (Short Authenticated Strings). I haven't thought through it too far, but I think speaking and verifying an 8 digit code (4 from each side) would reduce the MitM's chance of success down to 1-in-10k, no matter how much computation they spent trying for collisions. SAS is unidirectional, so I think both sides have to emit and compare a code (A->B + B->A), hence the 2x length requirement. But maybe 1x is enough. cheers, -Brian [1]: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.94.8504 _______________________________________________ Messaging mailing list [email protected] https://moderncrypto.org/mailman/listinfo/messaging
