Explicit Communication Revisited: Two New Attacks on Authentication Protocols

SSH and AKA are recent, practical protocols for secure connections over an otherwise unprotected network. This paper shows that, despite the use of public-key cryptography, SSH and AKA do not provide authentication as intended. The aws of SSH and AKA can be viewed as the result of their disregarding a basic principle for the design of sound authentication protocols: the principle that messages should be explicit.