As an important branch of quantum information, quantum cryptography (QC, or Quantum Key Distribution, QKD) is the process of sharing a secret bit string, known as the key, between two cooperative players (traditionally called Alice and Bob).

• 量子通信是量子信息中的一个重要部分，本文做的主要工作是在理论上分析量子密钥(或量子密钥分配)方案的安全性问题。