2,166 research outputs found
Secure Quantum Network Code without Classical Communication
We consider the secure quantum communication over a network with the presence
of a malicious adversary who can eavesdrop and contaminate the states. The
network consists of noiseless quantum channels with the unit capacity and the
nodes which applies noiseless quantum operations. As the main result, when the
maximum number m1 of the attacked channels over the entire network uses is less
than a half of the network transmission rate m0 (i.e., m1 < m0 / 2), our code
implements secret and correctable quantum communication of the rate m0 - 2m1 by
using the network asymptotic number of times. Our code is universal in the
sense that the code is constructed without the knowledge of the specific node
operations and the network topology, but instead, every node operation is
constrained to the application of an invertible matrix to the basis states.
Moreover, our code requires no classical communication. Our code can be thought
of as a generalization of the quantum secret sharing
Lightweight Security for Network Coding
Under the emerging network coding paradigm, intermediate nodes in the network
are allowed not only to store and forward packets but also to process and mix
different data flows. We propose a low-complexity cryptographic scheme that
exploits the inherent security provided by random linear network coding and
offers the advantage of reduced overhead in comparison to traditional
end-to-end encryption of the entire data. Confidentiality is achieved by
protecting (or "locking") the source coefficients required to decode the
encoded data, without preventing intermediate nodes from running their standard
network coding operations. Our scheme can be easily combined with existing
techniques that counter active attacks.Comment: Proc. of the IEEE International Conference on Communications (ICC
2008), Beijing, China, May 200
Using quantum key distribution for cryptographic purposes: a survey
The appealing feature of quantum key distribution (QKD), from a cryptographic
viewpoint, is the ability to prove the information-theoretic security (ITS) of
the established keys. As a key establishment primitive, QKD however does not
provide a standalone security service in its own: the secret keys established
by QKD are in general then used by a subsequent cryptographic applications for
which the requirements, the context of use and the security properties can
vary. It is therefore important, in the perspective of integrating QKD in
security infrastructures, to analyze how QKD can be combined with other
cryptographic primitives. The purpose of this survey article, which is mostly
centered on European research results, is to contribute to such an analysis. We
first review and compare the properties of the existing key establishment
techniques, QKD being one of them. We then study more specifically two generic
scenarios related to the practical use of QKD in cryptographic infrastructures:
1) using QKD as a key renewal technique for a symmetric cipher over a
point-to-point link; 2) using QKD in a network containing many users with the
objective of offering any-to-any key establishment service. We discuss the
constraints as well as the potential interest of using QKD in these contexts.
We finally give an overview of challenges relative to the development of QKD
technology that also constitute potential avenues for cryptographic research.Comment: Revised version of the SECOQC White Paper. Published in the special
issue on QKD of TCS, Theoretical Computer Science (2014), pp. 62-8
Byzantine Modification Detection in Multicast Networks With Random Network Coding
An information-theoretic approach for detecting Byzantine or adversarial modifications in networks employing random linear network coding is described. Each exogenous source packet is augmented with a flexible number of hash symbols that are obtained as a polynomial function of the data symbols. This approach depends only on the adversary not knowing the random coding coefficients of all other packets received by the sink nodes when designing its adversarial packets. We show how the detection probability varies with the overhead (ratio of hash to data symbols), coding field size, and the amount of information unknown to the adversary about the random code
Composability in quantum cryptography
In this article, we review several aspects of composability in the context of
quantum cryptography. The first part is devoted to key distribution. We discuss
the security criteria that a quantum key distribution protocol must fulfill to
allow its safe use within a larger security application (e.g., for secure
message transmission). To illustrate the practical use of composability, we
show how to generate a continuous key stream by sequentially composing rounds
of a quantum key distribution protocol. In a second part, we take a more
general point of view, which is necessary for the study of cryptographic
situations involving, for example, mutually distrustful parties. We explain the
universal composability framework and state the composition theorem which
guarantees that secure protocols can securely be composed to larger
applicationsComment: 18 pages, 2 figure
- …