量子计算机对现代通信安全提出了严重挑战，量子保密通信是应对这一挑战的重要技术。1984年Bennett和Brassard提出的量子密钥分发，1999年Hillery、Bužek、Berthiaume提出的量子秘密共享和2000年龙桂鲁、刘晓曙提出的量子安全直接通信（Quantum Secure Direct Communication，简称QSDC、量子直通）[1]是三个最主要的量子保密通信理论。
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