Am 07.10.2014 um 02:25 schrieb Dave Crocker: > On 10/6/2014 4:44 PM, Tamme Schichler wrote: >> The problem is that B has a history of lying >> about such conversations, so A wants to be able to prove as much as >> becomes necessary to deflect allegations, but also little as possible to >> protect the privacy of either side or third parties (or the other way >> around, as usual the solution would ideally be symmetric). > > > Sounds like a classic requirement for Non-Repudiation of Recipient: > > http://www.cse.scu.edu/~tschwarz/coen351_06/PPtPre/Nonrepudiation.ppt > > http://ccr.sigcomm.org/archive/1996/jan96/ccr-9601-coffey.ps > > d/ >
Thanks for these links, the proofs of receipt are definitely something I need to look into. Ideally it should be simultaneous, but I don't know a scheme that can do that without a witness. (I think. I remember reading about some Bitcoin-related schemes involving forcing someone to reveal a secret in the process of acquiring something, but that may just have used the block-chain for witnessing it instead.) Since I'm thinking about a chat protocol it could be feasible to use some kind of alternating system that prevents the conversation from progressing without the previous proofs. Being able to use a non-repudiation server instead would definitely be better though. Unfortunately I don't know any existing services that can do this programmatically, but it should be easy enough to allow someone to host one on-the-fly if I get around to implementing the main protocol. Tamme _______________________________________________ Messaging mailing list [email protected] https://moderncrypto.org/mailman/listinfo/messaging
