Improvement of Quantum Protocols for Secure Multi-Party Summation

Secure multi-party quantum summation is an important branch of secure multi-party quantum computation. Recently, Ji et al. suggested a secure multi-party quantum summation scheme based on the entanglement swapping between thed-level Bell state and thed-leveln+1-particle cat state (Quantum Inf Process (2019)18:168). In this paper, it is pointed out that Ji et al.'s secure multi-party quantum summation scheme has a security loophole, i.e., the third party (TP) can obtain the secret numbers ofncommunicants without being discovered. Then, in order to avoid this security loophole, an improvement is suggested by adopting the method of encrypting the secret integers ofncommunicants with a pre-shared private key sequence among them.