Attacks on Fixed Apparatus Quantum Key Distribution Schemes
This reveals a critical security flaw in practical quantum key distribution systems, which is incremental but important for the field of quantum cryptography.
The paper demonstrates that quantum key distribution implementations with fixed receiver apparatus are completely insecure against a strong eavesdropper with one-time access, posing a risk to recent implementations.
We consider quantum key distribution implementations in which the receiver's apparatus is fixed and does not depend on his choice of basis at each qubit transmission. We show that, although theoretical quantum key distribution is proven secure, such implementations are totally insecure against a strong eavesdropper that has one-time (single) access to the receiver's equipment. The attack we present here, the "fixed-apparatus attack" causes a potential risk to the usefulness of several recent implementations.