A fast quantum mechanical algorithm for database search
STOC '96 Proceedings of the twenty-eighth annual ACM symposium on Theory of computing
A proof of the security of quantum key distribution (extended abstract)
STOC '00 Proceedings of the thirty-second annual ACM symposium on Theory of computing
Quantum Key Distribution and String Oblivious Transfer in Noisy Channels
CRYPTO '96 Proceedings of the 16th Annual International Cryptology Conference on Advances in Cryptology
Quantum search on bounded-error inputs
ICALP'03 Proceedings of the 30th international conference on Automata, languages and programming
Security of quantum key distribution with imperfect devices
Quantum Information & Computation
Proof of security of quantum key distribution with two-way classical communications
IEEE Transactions on Information Theory
On the security of αη: response to 'some attacks on quantum-based cryptographic protocols'
Quantum Information & Computation
A simple participant attack on the brádler-dušek protocol
Quantum Information & Computation
Quantum Information Processing
Cryptanalysis of dynamic quantum secret sharing
Quantum Information Processing
Attack and improvements of fair quantum blind signature schemes
Quantum Information Processing
Arbitrated quantum signature of classical messages without using authenticated classical channels
Quantum Information Processing
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Quantum-based cryptographic protocols are often said to enjoy security guaranteed by the fundamental laws of physics. However, even carefully designed quantum-based cryptographic schemes may be susceptible to subtle attacks that are outside the original design. As an example, we give attacks against a recently proposed "secure communication using mesoscopic coherent states", which employs mesoscopic states, rather than single-photon states. Our attacks can be used either as a known-plaintext attack or in the case where the plaintext has not been randomized. One of our attacks requires beamsplitters and the replacement of a lossy channel by a lossless one. It is successful provided that the original loss in the channel is so big that Eve can obtain 2k copies of what Bob receives, where k is the length of the seed key pre-shared by Alice and Bob. In addition, substantial improvements over such an exhaustive key search attack can be made, whenever a key is reused. Furthermore, we remark that, under the same assumption of a known or non-random plaintext, Grover's exhaustive key search attack can be applied directly to "secure communication using mesoscopic coherent states", whenever the channel loss is more than 50 percent. Therefore, as far as information-theoretic security is concerned, optically ampli?ed signals necessarily degrade the security of the proposed scheme, when the plaintext is known or non-random. Our attacks apply even if the mesoscopic scheme is used only for key generation with a subsequent use of the key for one-time-pad encryption. Studying those attacks can help us to better define the risk models and parameter spaces in which quantum-based cryptographic schemes can operate securely. Finally, we remark that our attacks do not affect standard protocols such as Bennett-Brassard BB84 protocol or Bennett B92 protocol, which rely on single-photon signals.