High-efficiency quantum digital signature scheme for signing long messages

Quantum digital signature (QDS) is based on the laws of quantum physics, and can provide unconditional security for signing messages between remote multi-party users. To date, different QDS protocols have been proposed and corresponding security analysis has been done. Just most security analyses are directed against signing single-bit messages, and the security cannot be ensured when signing multi-bit messages if one simply puts blocks together. Recently, T.Y. Wang et al. analyzed the security under this situation and gave a solution for eliminating potential eavesdropping attacks. However, its efficiency is relatively low since they need to consume more than 2n-bit signatures to sign a classical n-bit message. In this paper, we propose a high efficient approach for signing multi-bit messages. As a result, the efficiency can be improved with 36.92% when signing a 128-bit message compared with using T.Y. Wang et al.’s method. And the improvement is even larger when signing longer messages.