Quantum Eavesdropping without Interception: An Attack Exploiting the Dead Time of Single Photon Detectors

Abstract

The security of quantum key distribution (QKD) can easily be obscured if the eavesdropper can utilize technical imperfections of the actual implementation. Here we describe and experimentally demonstrate a very simple but highly effective attack which even does not need to intercept the quantum channel at all. Only by exploiting the dead time effect of single photon detectors the eavesdropper is able to gain (asymptotically) full information about the generated keys without being detected by state-of-the-art QKD protocols. In our experiment, the eavesdropper inferred up to 98.8% of the key correctly, without increasing the bit error rate between Alice and Bob significantly. Yet, we find an evenly simple and effective countermeasure to inhibit this and similar attacks.

References in corpus (8)

• Hacking commercial quantum cryptography systems by tailored bright illumination
• Long distance decoy state quantum key distribution in optical fiber
• Controlling passively-quenched single photon detectors by bright light
• After-gate attack on a quantum cryptosystem
• Breaking a quantum key distribution system through a timing side channel
• Continuous operation of high bit rate quantum key distribution
• Avoiding the Detector Blinding Attack on Quantum Cryptography
• Detector dead-time effects and paralyzability in high-speed quantum key distribution