On Mon, Feb 18, 2013 at 8:51 PM, Ileana <[email protected]> wrote: > We are writing an article: https://fairieunderground.info/node/149 > Any other comments or additional details are appreciated.
You're really understating OTR's authentication advantages. The SMP handshake allows you to use past social context to do a highly secure (brute force proof, it's a ZKP) authentication handshake without having to previously establish a secure channel to transmit high entropy data in... if you had a channel to securely establish a hidden service ID you might as well have exchanged a long lived symmetric key (And gained some hypothetical security against QC enabled adversaries). The availability point is really about the underlying transport with OTR. Presumably you could use OTR over personally run jabber servers over tor to get similar properties, though in both cases the tor network itself is subject to denial of service (and, in general, hidden services seem a bit more brittle than tor is over all). > Encryption secrecy Perfect forward secrecy Perfect forward secrecy > Proof of Communication Retrieving hidden service key is proof of > running the service This sort of misses OTR's main protocol innovation— it conducts its operation without binding the content with a cryptographic signature. So if you're talking to a traitor they can't log your signed packets and then prove to a third party what you said and yet the person you spoke to knows for sure it was you. So there are two different kinds of denyability at play— being able to deny a conversation happened (which perhaps use with tor provides although traffic analysis is _very_ powerful) and being able to deny _what_ you said in the face of a defecting counterparty. I don't believe the torchat provides denyable authentication. I'm not sure if torchat has denyable authentication or if something in the tor transport breaks that. Neither torchat nor OTR use 256 bit AES, they both use 128 bit AES. _______________________________________________ OTR-dev mailing list [email protected] http://lists.cypherpunks.ca/mailman/listinfo/otr-dev
