Towards a formal definition of security for quantum protocols
Towards a formal definition of security for quantum protocols
Correcting errors without leaking partial information
Proceedings of the thirty-seventh annual ACM symposium on Theory of computing
Fuzzy Extractors: How to Generate Strong Keys from Biometrics and Other Noisy Data
SIAM Journal on Computing
Key Agreement from Close Secrets over Unsecured Channels
EUROCRYPT '09 Proceedings of the 28th Annual International Conference on Advances in Cryptology: the Theory and Applications of Cryptographic Techniques
Non-malleable extractors and symmetric key cryptography from weak secrets
Proceedings of the forty-first annual ACM symposium on Theory of computing
Improving the Security of Quantum Protocols via Commit-and-Open
CRYPTO '09 Proceedings of the 29th Annual International Cryptology Conference on Advances in Cryptology
The operational meaning of min- and max-entropy
IEEE Transactions on Information Theory
Secure identification and QKD in the bounded-quantum-storage model
CRYPTO'07 Proceedings of the 27th annual international cryptology conference on Advances in cryptology
A tight high-order entropic quantum uncertainty relation with applications
CRYPTO'07 Proceedings of the 27th annual international cryptology conference on Advances in cryptology
Randomness extraction via δ-biased masking in the presence of a quantum attacker
TCC'08 Proceedings of the 5th conference on Theory of cryptography
Privacy amplification with asymptotically optimal entropy loss
Proceedings of the forty-second ACM symposium on Theory of computing
Secure authentication from a weak key, without leaking information
EUROCRYPT'11 Proceedings of the 30th Annual international conference on Theory and applications of cryptographic techniques: advances in cryptology
Universally composable privacy amplification against quantum adversaries
TCC'05 Proceedings of the Second international conference on Theory of Cryptography
Secure authentication from a weak key, without leaking information
EUROCRYPT'11 Proceedings of the 30th Annual international conference on Theory and applications of cryptographic techniques: advances in cryptology
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We study the problem of authentication based on a weak key in the information-theoretic setting. A key is weak if its min-entropy is an arbitrary small fraction of its bit length. This problem has recently received considerable attention, with different solutions optimizing different parameters. We study the problem in an extended setting, where the weak key is a one-time session key that is derived from a public source of randomness with the help of a (potentially also weak) long-term key. Our goal now is to authenticate a message by means of the weak session key in such a way that (nearly) no information on the long-term key is leaked. Ensuring privacy of the long-term key is vital for the long-term key to be re-usable. Previous work has not considered such a privacy issue, and previous solutions do not seem to satisfy this requirement. We show the existence of a practical four-round protocol that provides message authentication from a weak session key and that avoids non-negligible leakage on the long-term key. The security of our scheme also holds in the quantum setting where the adversary may have limited quantum side information on the weak session key. As an application of our scheme, we show the existence of an identification scheme in the bounded quantum storage model that is secure against a man-in-the-middle attack and that is truly password-based: it does not need any high entropy key, in contrast to the scheme proposed by Damgård et al.