# Trojan-horse attacks threaten the security of practical quantum cryptography

@article{Jain2014TrojanhorseAT, title={Trojan-horse attacks threaten the security of practical quantum cryptography}, author={Nitin Jain and Elena Anisimova and Imran Khan and Vadim Makarov and Christoph Marquardt and Gerd Leuchs}, journal={New Journal of Physics}, year={2014}, volume={16} }

A quantum key distribution (QKD) system may be probed by an eavesdropper Eve by sending in bright light from the quantum channel and analyzing the back-reflections. We propose and experimentally demonstrate a setup for mounting such a Trojan-horse attack. We show it in operation against the quantum cryptosystem Clavis2 from ID Quantique, as a proof-of-principle. With just a few back-reflected photons, Eve discerns Bobʼs (secret) basis choice, and thus the raw key bit in the Scarani–Acín–Ribordy…

## 108 Citations

### Detection Efficiency Mismatch and Finite-Key-Size Attacks on Practical Quantum Cryptography Systems

- Computer Science
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This thesis presents three experimental studies of attacks on quantum key distribution (QKD) systems, including a demonstration of Eve’s ability to force a commercial system to distill a key from a raw key of a short length, where the asymptotic assumption of security claimed by the manufacturer might not hold.

### Hacking Alice's box in continuous-variable quantum key distribution

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This paper considers an attack on a coherent-state protocol, where Eve not only taps the main communication channel but also hacks Alice's device, and shows how the key rate rapidly deteriorates for increasing photons.

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### Risk Analysis of Trojan-Horse Attacks on Practical Quantum Key Distribution Systems

- Computer Science, PhysicsIEEE Journal of Selected Topics in Quantum Electronics
- 2015

This work presents a risk analysis of Trojan-horse attacks on quantum key distribution systems based on extensive spectral measurements, and indicates the existence of wavelength regimes, where the attacker gains considerable advantage as compared to launching an attack at 1550 nm.

### Practical security bounds against the Trojan-horse attack in quantum key distribution

- Physics, Computer Science
- 2015

The Trojan-horse attack is turned into an information leakage problem and the system security is quantified and related to the specification of the optical elements most relevant to security.

### Invisible Trojan-horse attack

- PhysicsScientific Reports
- 2017

It is demonstrated experimentally that the noise response of the detectors to bright pulses is greatly reduced, and by modeling that the same attack will succeed, the invisible nature of the attack poses a threat to the security of practical QKD if proper countermeasures are not adopted.

### Quantum key distribution with hacking countermeasures and long term field trial

- Computer ScienceScientific Reports
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A QKD system designed with this goal in mind is reported, providing a more resilient target against possible hacking attacks including Trojan horse, detector blinding, phase randomisation and photon number splitting attacks.

### Quantum man-in-the-middle attack on the calibration process of quantum key distribution

- Computer ScienceScientific Reports
- 2018

This paper reveals the security risk of the calibration process of a passive-basis-choice BB84 QKD system by launching a quantum man-in-the-middle attack which intercepts all calibration signals and resends faked ones, and proposes a basis-dependent detector efficiency mismatch (BEM) based faked states attack on a single photon BB84QKD to stress the threat of BEM.

### Quantum Hacking in the Age of Measurement-Device-Independent Quantum Cryptography

- Computer Science
- 2018

This thesis further investigates the practical security of quantum cryptography in and beyond MDI quantum cryptography, and shows that detector-device-independent (DDI) QKD security is not equivalent to that of MDIQKD and, further, that DDI QKKD is insecure against detector side-channel attacks.

### Backflash Light as a Security Vulnerability in Quantum Key Distribution Systems

- Computer ScienceArXiv
- 2020

This work focuses on a particular effect known as backflash light, which can be a source of eavesdropping attacks and highlights the method for quantifying backflash emission and the different ways to mitigate this effect.

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