Secure Identification and QKD in the Bounded-Quantum-Storage Model

We consider the problem of secure identification: user U proves to server S that he knows an agreed (possibly low-entropy) password w, while giving away as little information on w as possible, namely the adversary can exclude at most one possible password for each execution of the scheme. We propose a solution in the bounded-quantumstorage model, where U and S may exchange qubits, and a dishonest party is assumed to have limited quantum memory. No other restriction is posed upon the adversary. An improved version of the proposed identification scheme is also secure against a man-in-the-middle attack, but requires U and S to additionally share a high-entropy key k. However, security is still guaranteed if one party loses k to the attacker but notices the loss. In both versions of the scheme, the honest participants need no quantum memory, and noise and imperfect quantum sources can be tolerated. The schemes compose sequentially, and w and k can securely be re-used. A small modification ...

• Type: Conference
• Year: 2007
• Where: CRYPTO
• Authors: Ivan Damgård, Serge Fehr, Louis Salvail, Christian Schaffner
• Keywords: Authenticated Channels, CRYPTO 2007, Cryptology, Identification Scheme, Quantum Memory