Abstract: Quantum communication is the only strictly proved communication technology with unconditional security in principle. In a narrow sense, quantum communication refers to quantum key distribution, which is proved to be absolutely security based on ideal BB84 protocol. However, the idealized conditions can not be fully satisfied by real systems, wherein nonideal light sources readily get photon number splitting attack, and this security problem can be well solved by BB84 decoy state quantum key distribution.

Key words: quantum key distribution, photon number splitting attack, decoy state, unconditional security

摘要： 量子通信是唯一得到严格证明、能从原理上确保无条件安全的通信技术.狭义地讲，量子通信技术指的是量子密钥分发技术，基于理想BB84协议的量子密钥分发技术被证明是绝对安全的，而现实系统无法完全满足理想化条件，其中非理想光源很容易受到光子数分束攻击，而基于BB84协议的诱骗态量子密钥分发方案能很好地解决非理想光源的安全通信问题.

关键词: 量子密钥分发, 光子数分束攻击, 诱骗态, 无条件安全