A simple proof of the unconditional security of relativistic quantum cryptography

Abstract

A simple proof of the unconditional security of a relativistic quantum cryptosystem based on orthogonal states is proposed. Restrictions imposed by special relativity allow to substantially simplify the proof compared with the non-relativistic cryptosystems involving non-orthogonal states. Important for the proposed protocol is the spatio-temporal structure of the quantum states which is actually ignored in the non-relativistic protocols employing only the structure of the state space of the information carriers. As a consequence, the simplification arises because of the inefficiency of collective measurements which constitute the major problem in the non-relativistic case.

11 pages, 1 figure (typos in Eqs. 2, 7 and 8 are corrected)

References in corpus (3)

• Quantum cryptography: Public key distribution and coin tossing
• Simple Proof of Security of the BB84 Quantum Key Distribution Protocol
• Teleportation of the Relativistic Quantum Field

Cited by in corpus (1)

• Is the security of quantum cryptography guaranteed by the laws of physics?