847 research outputs found
Insider-proof encryption with applications for quantum key distribution
It has been pointed out that current protocols for device independent quantum
key distribution can leak key to the adversary when devices are used repeatedly
and that this issue has not been addressed. We introduce the notion of an
insider-proof channel. This allows us to propose a means by which devices with
memories could be reused from one run of a device independent quantum key
distribution protocol to the next while bounding the leakage to Eve, under the
assumption that one run of the protocol could be completed securely using
devices with memories.Comment: 20 pages, version 2: new presentation introducing the insider-proof
channel as a cryptographic elemen
Can you sign a quantum state?
Cryptography with quantum states exhibits a number of surprising and counterintuitive features. In a 2002 work, Barnum et al. argued informally that these strange features should imply that digital signatures for quantum states are impossible (Barnum et al., FOCS 2002).
In this work, we perform the first rigorous study of the problem of signing quantum states. We first show that the intuition of Barnum et al. was correct, by proving an impossibility result which rules out even very weak forms of signing quantum states. Essentially, we show that any non-trivial combination of correctness and security requirements results in negligible security. This rules out all quantum signature schemes except those which simply measure the state and then sign the outcome using a classical scheme. In other words, only classical signature schemes exist.
We then show a positive result: it is possible to sign quantum states, provided that they are also encrypted with the public key of the intended recipient. Following classical nomenclature, we call this notion quantum signcryption. Classically, signcryption is only interesting if it provides superior efficiency to simultaneous encryption and signing. Our results imply that, quantumly, it is far more interesting: by the laws of quantum mechanics, it is the only signing method available.
We develop security definitions for quantum signcryption, ranging from a simple one-time two-user setting, to a chosen-ciphertext-secure many-time multi-user setting. We also give secure constructions based on post-quantum public-key primitives. Along the way, we show that a natural hybrid method of combining classical and quantum schemes can be used to "upgrade" a secure classical scheme to the fully-quantum setting, in a wide range of cryptographic settings including signcryption, authenticated encryption, and chosen-ciphertext security
Quantum Cryptography
Quantum cryptography is a new method for secret communications offering the
ultimate security assurance of the inviolability of a Law of Nature. In this
paper we shall describe the theory of quantum cryptography, its potential
relevance and the development of a prototype system at Los Alamos, which
utilises the phenomenon of single-photon interference to perform quantum
cryptography over an optical fiber communications link.Comment: 36 pages in compressed PostScript format, 10 PostScript figures
compressed tar fil
Identity-Concealed Authenticated Encryption from Ring Learning With Errors (Full version)
Authenticated encryption (AE) is very suitable for a resources constrained environment for it needs less computational costs and AE has become one of the important technologies of modern communication security. Identity concealment is one of research focuses in design and analysis of current secure transport protocols (such as TLS1.3 and Google\u27s QUIC). In this paper, we present a provably secure identity-concealed authenticated encryption in the public-key setting over ideal lattices, referred to as RLWE-ICAE. Our scheme can be regarded as a parallel extension of higncryption scheme proposed by Zhao (CCS 2016), but in the lattice-based setting. RLWE-ICAE can be viewed as a monolithic integration of public-key encryption, key agreement over ideal lattices, identity concealment and digital signature. The security of RLWE-ICAE is directly relied on the Ring Learning with Errors (RLWE) assumption. Two concrete choices of parameters are provided in the end
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