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arXiv · 0708.0709

Quantum cryptography with finite resources: unconditional security bound for discrete-variable protocols with one-way post-processing

Valerio Scarani·Renato Renner
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Abstract

We derive a bound for the security of QKD with finite resources under one-way post-processing, based on a definition of security that is composable and has an operational meaning. While our proof relies on the assumption of collective attacks, unconditional security follows immediately for standard protocols like Bennett-Brassard 1984 and six-states. For single-qubit implementations of such protocols, we find that the secret key rate becomes positive when at least N\sim 10^5 signals are exchanged and processed. For any other discrete-variable protocol, unconditional security can be obtained using the exponential de Finetti theorem, but the additional overhead leads to very pessimistic estimates.

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Valerio Scarani, Renato Renner. 2008-06-01. Quantum cryptography with finite resources: unconditional security bound for discrete-variable protocols with one-way post-processing. https://doi.org/10.1103/physrevlett.100.200501

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