Efficient Device-Independent Quantum Key Distribution Esther Hänggi Renato Renner Stefan Wolf ETH Zürich EUROCRYPT 2010 31st May 2010
Quantum Key Distribution 1 1 'Traditional' QKD relies on: - Laws of Quantum Mechanics - Exact Specification of Devices
Why Device-Independence? 45° 45° 1 1 need to trust devices + manufacturer Example: BB84 Entanglement-based [BBM92] ([E91]) Other measurements or systems insecure
Quantum Key Distribution 1 1 no signaling 'Traditional' QKD relies on: - Laws of Quantum Mechanics no need to trust manufacturer - Exact Specification of Devices - Security of Labs
Systems and Security
PXYZ|UVW PXYZ|UVW W Z U V Y X Systems and Security random system [Maurer 02] U V Y PXYZ|UVW PXYZ|UVW X Condition: no signaling „shielded labs“
PXYZ|UVW W Z U V Y X Pr[XY=UV]=1- XY=UV Systems and Security 4-insecure secure [Barrett,Hardy,Kent 05]: different system 0 0 0 1 1 0 1 1 U V X Y → or But: - inefficient Privacy amplification? - noise-intolerant [BBR98],[ILL99]
Privacy Amplification 4 4 4 individual attacks general attacks [HRW08] individual attacks [AGM06][SGBMPA06] [AMP06] 4 4 4
Privacy Amplification 4 (4)n 4 4 general attacks + no signaling within labs [Masanes 09] (non-constructive) [this paper]: XOR deterministic privacy amplification function 4 (4)n 4 4
The Protocol - measure
PXY|UV The Protocol - measure - check correlation - information reconciliation (random linear code) PXY|UV - privacy amplification secure key
Conclusion Secure key - against most general attacks - universally composable - works based on (observable) violation of Bell Inequality - ONLY requirement: no signaling - device-independent Open question: relaxing of no signaling condition?
Thank you Full version: http://arxiv.org/abs/0911.4171