Attacking quantum key distribution by light injection via ventilation openings

Understand

Quantum cryptography promises security based on the laws of physics with proofs of security against attackers of unlimited computational power.

• However, deviations from the original assumptions allow quantum hackers to compromise the system.
• We present a side channel attack that takes advantage of ventilation holes in optical devices to inject additional photons that can leak information about the secret key.
• We experimentally demonstrate light injection on an ID~Quantique Clavis2 quantum key distribution platform and show that this may help an attacker to learn information about the secret key.