View source for Security proof (quantum cryptography)

A '''security proof''' in quantum cryptography is a formal argument that a protocol's key remains information-theoretically secure against all attacks allowed by quantum mechanics, typically reducing the protocol's security to bounds on the [[Holevo information]] or trace distance. The security proof for [[Decoy State QKD|decoy state QKD]] achieves asymptotic rates comparable to perfect single-photon sources by bounding the multi-photon contribution through intensity-dependent detection statistics.