14,718 research outputs found
Quantum Cryptography in Practice
BBN, Harvard, and Boston University are building the DARPA Quantum Network,
the world's first network that delivers end-to-end network security via
high-speed Quantum Key Distribution, and testing that Network against
sophisticated eavesdropping attacks. The first network link has been up and
steadily operational in our laboratory since December 2002. It provides a
Virtual Private Network between private enclaves, with user traffic protected
by a weak-coherent implementation of quantum cryptography. This prototype is
suitable for deployment in metro-size areas via standard telecom (dark) fiber.
In this paper, we introduce quantum cryptography, discuss its relation to
modern secure networks, and describe its unusual physical layer, its
specialized quantum cryptographic protocol suite (quite interesting in its own
right), and our extensions to IPsec to integrate it with quantum cryptography.Comment: Preprint of SIGCOMM 2003 pape
Tight Finite-Key Analysis for Quantum Cryptography
Despite enormous progress both in theoretical and experimental quantum
cryptography, the security of most current implementations of quantum key
distribution is still not established rigorously. One of the main problems is
that the security of the final key is highly dependent on the number, M, of
signals exchanged between the legitimate parties. While, in any practical
implementation, M is limited by the available resources, existing security
proofs are often only valid asymptotically for unrealistically large values of
M. Here, we demonstrate that this gap between theory and practice can be
overcome using a recently developed proof technique based on the uncertainty
relation for smooth entropies. Specifically, we consider a family of
Bennett-Brassard 1984 quantum key distribution protocols and show that security
against general attacks can be guaranteed already for moderate values of M.Comment: 11 pages, 2 figure
General theory of decoy-state quantum cryptography with source errors
The existing theory of decoy-state quantum cryptography assumes the exact
control of each states from Alice's source. Such exact control is impossible in
practice. We develop the theory of decoy-state method so that it is
unconditionally secure even there are state errors of sources, if the range of
a few parameters in the states are known. This theory simplifies the practical
implementation of the decoy-state quantum key distribution because the
unconditional security can be achieved with a slightly shortened final key,
even though the small errors of pulses are not corrected.Comment: Our results can be used securely for any source of diagonal states,
including the Plug-&-Play protocol with whatever error pattern, if we know
the ranges of errors of a few parameter
- …