Paper 2020/1231 Original: eprint.iacr.org/2020/1231 ↗

vault1317/signal-dakez: An authenticated key exchange protocol with a public key concealing and a participation deniability designed for secure messaging

Abstract

A deniable authenticated key exchange can establish a secure communication channel while leaving no cryptographic evidence of communication. Some well-designed protocol today, even in the case of betrayal by some participants and disclosure of long-term key materials, cannot leave any cryptographic evidence. However, this is no longer enough: If “Big data” technology is used to analyse data fetched from pivotal nodes, it’s not difficult to register your identity through your long-term public keys. (although it can’t be a solid evidence due to deniability) In this article, we have analysed the advantages and disadvantages of existing solutions which are claimed to be deniable to some degree, and proposed an authenticated key exchange protocol that is able to conceal the public keys from the outside of the secure channel, and deniable to some degree, and a reference implementation is provided.