Lighting Two Candles With One Flame: An Unaided Human Identification Protocol With Security Beyond Conventional Limit

Designing an efficient protocol for avoiding the threat of recording based attack in presence of a powerful eavesdropper remains a challenge for more than two decades. During authentication, the absence of any secure link between the prover and verifier makes things even more vulnerable as, after observing a threshold challenge-response pair, users' secret may easily get derived due to information leakage. Existing literature only present new methodologies with ensuring superior aspects over previous ones, while ignoring the aspects on which their proposed schemes cope poorly. Unsurprisingly, most of them are far from satisfactory - either are found far from usable or lack of security features. To overcome this issue, we first introduce the concept of "leakage control" which puts a bar on the natural information leakage rate and greatly helps in increasing both the usability and security standards. Not just prevention, but also, by introducing the threat detection strategy (based on the concept of honeyword), our scheme "lights two candles". It not only eliminates the long terms security and usability conflict under the practical scenario, but along with threat detection from the client side, it is capable of protecting the secret at the server side under the distributed framework, and thus, guaranteeing security beyond the conventional limit.