Entanglement based six-state quantum cryptography protocol: exact proof of security

S. P. Kulik and S. N. Molotkov

Laser Physics Letters, 20, 5, 055203-055209 (2023)

A novel quantum key distribution protocol is proposed, which uses 6states of three states in two bases. The protocol provides a greater range of keydistribution compared to known QKD protocols. The protocol has an accurate proofof secrecy based on fundamental entropy uncertainty relations, the use of which ispossible with the entanglement version of the protocol. The implementation of theprotocol does not require adjustment of the polarization state at the output of thecommunication line, since the receiving side does not use active polarization-sensitiveelements - phase modulators, which virtually excludes active probing of the activeelements of the system.