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Security of quantum key distribution from generalised entropy accumulation
1Institute for Theoretical Physics, ETH Zürich, 8093, Zürich, Switzerland. tmetger@ethz.ch.
Nature Communications
|August 29, 2023
Summary
Quantum key distribution (QKD) security against general attacks is proven to be equivalent to security against collective attacks. This simplifies security proofs for QKD protocols, reducing them to a numerical computation.
Area of Science:
- Quantum Information Science
- Cryptography
- Theoretical Computer Science
Background:
- Quantum Key Distribution (QKD) enables secure key establishment over insecure channels.
- Proving finite-size key security against general attacks is a significant challenge in QKD.
- Collective attacks offer a simpler security model compared to general attacks.
Purpose of the Study:
- To develop a formal framework for analyzing general QKD protocols.
- To demonstrate that security against general attacks can be reduced to security against collective attacks for protocols within this framework.
- To simplify the security proof process for QKD.
Main Methods:
- Development of a formal framework for general QKD protocols.
- Application of generalised entropy accumulation, an information-theoretic tool.
- Reduction of general attack security to collective attack security.
Main Results:
- A formal framework is established for general QKD protocols.
- Security against general attacks is shown to be equivalent to security against collective attacks.
- The security proof is reduced to a numerical computation.
Conclusions:
- The security analysis of general QKD protocols is significantly simplified.
- The developed framework accommodates generic prepare-and-measure protocols directly.
- This work paves the way for more practical and rigorously secure QKD implementations.
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