A quantum digital signature (QDS) is guaranteed by the laws of quantum physics and can provide unconditional security to authenticate classical messages. Previous QDS protocols that shared secret keys could be realized using discrete-variable quantum key distribution (DV-QKD), for which the DV-QKD relied on extreme requirements like single-photon detection and extremely weak pulses of light. QDS protocols are mainly focused on how to sign a one-bit message rather than multi-bit messages. In this paper, we present a continuous-variable quantum digital signature (CV-QDS) protocol for signing multi-bit messages. The CV-QDS protocol has better compatibility with existing communication systems and the encoding strategy for multi-bit messages is simpler than before. We hope the continuous-variable protocol could further improve the performance of QDS.

量子物理定律可以保证量子数字签名（QDS），并且可以提供无条件的安全性来认证经典消息。以前的共享秘密密钥的QDS协议可以使用离散变量量子密钥分发（DV-QKD）来实现，为此，DV-QKD依赖于极端要求，例如单光子检测和极弱的光脉冲。QDS协议主要关注于如何对一位消息而不是多位消息进行签名。在本文中，我们提出了一种用于对多位消息进行签名的连续可变量子数字签名（CV-QDS）协议。CV-QDS协议与现有通信系统具有更好的兼容性，并且用于多位消息的编码策略比以前更简单。我们希望连续变量协议可以进一步提高QDS的性能。