We propose secure protocols for user authenticated quantum key distribution on jammable public channels between two parties, Alice and Bob. Via an arbitrator, Trent, these protocols provide data integrity and mutual identification of the messenger and recipient. The first three are based on single-photon generation and detection. The first and second require (initially) an unjammable channel between the arbitrator and each party. The third requires one broadcast from the arbitrator, disclosing what type of deterministic modification of the states sent through the quantum channel was done by him. The fourth and fifth protocols are based on two-particle entanglement with a preselection of nonorthogonal superpositions of Bell states. These two protocols also require one broadcast from the arbitrator disclosing the type of entangled state in each sending.

• Received 19 November 1999

DOI:https://doi.org/10.1103/PhysRevA.62.022305