QSNP
Back to glossary

Measurement-DI QKD

Definition:
Measurement-device-independent quantum key distribution (MDI-QKD) is a QKD protocol designed to eliminate all detector side-channel attacks, one of the main vulnerabilities in conventional QKD systems. It ensures that security does not rely on trusted measurement devices.

Scientific context:
In standard QKD setups, imperfections in the detectors can be exploited by adversaries through techniques like blinding attacks or time-shift attacks. MDI-QKD addresses this by changing the architecture: instead of Alice sending photons directly to Bob, both Alice and Bob send quantum states to a central untrusted relay, where a Bell state measurement is performed.

Key features of MDI-QKD include:

  • Immunity to all detector side channels.

  • Compatibility with standard optical components, even in the presence of low detection efficiency and channel loss.

  • No need for near-unity efficiency detectors, qubit amplifiers, or quantum non-demolition measurements.

MDI-QKD can double the secure distance achievable with conventional systems using standard lasers and yields much higher key generation rates than fully device-independent QKD, while offering a high degree of practical security.

Did you know?
MDI-QKD combines real-world practicality with strong security guarantees. It bridges the gap between conventional QKD and the more demanding fully device-independent QKD protocols, making it a leading candidate for scalable quantum networks.