Information-theoretic key agreement: from weak to strong secrecy for free
EUROCRYPT'00 Proceedings of the 19th international conference on Theory and application of cryptographic techniques
New bounds in secret-key agreement: the gap between formation and secrecy extraction
EUROCRYPT'03 Proceedings of the 22nd international conference on Theory and applications of cryptographic techniques
Quantum Information & Computation
The universal composable security of quantum key distribution
TCC'05 Proceedings of the Second international conference on Theory of Cryptography
Universally composable privacy amplification against quantum adversaries
TCC'05 Proceedings of the Second international conference on Theory of Cryptography
Uncertainty, Monogamy, and Locking of Quantum Correlations
IEEE Transactions on Information Theory
General paradigm for distilling classical key from quantum states
IEEE Transactions on Information Theory
Security of trusted repeater quantum key distribution networks
Journal of Computer Security - EU-Funded ICT Research on Trust and Security
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Assume that two distant parties, Alice and Bob, as well as an adversary, Eve, have access to (quantum) systems prepared jointly according to a tripartite state ρABE. In addition, Alice and Bob can use local operations and authenticated public classical communication. Their goal is to establish a key which is unknown to Eve. We initiate the study of this scenario as a unification of two standard scenarios: (i) key distillation (agreement) from classical correlations and (ii) key distillation from pure tripartite quantum states. Firstly, we obtain generalisations of fundamental results related to scenarios (i) and (ii), including upper bounds on the key rate, i.e., the number of key bits that can be extracted per copy of ρABE. Moreover, based on an embedding of classical distributions into quantum states, we are able to find new connections between protocols and quantities in the standard scenarios (i) and (ii). Secondly, we study specific properties of key distillation protocols. In particular, we show that every protocol that makes use of preshared key can be transformed into an equally efficient protocol which needs no pre-shared key. This result is of practical significance as it applies to quantum key distribution (QKD) protocols, but it also implies that the key rate cannot be locked with information on Eve's side. Finally, we exhibit an arbitrarily large separation between the key rate in the standard setting where Eve is equipped with quantum memory and the key rate in a setting where Eve is only given classical memory. This shows that assumptions on the nature of Eve's memory are important in order to determine the correct security threshold in QKD.