Abstract: In order to solve the problem that the quantum key agreement protocols immune to collective noise have low qubit efficiency, two new quantum key agreement protocols are proposed based on logical Bell states. They immune to the collective-dephasing noise and the collective-rotation noise, respectively. Two participants in the protocols can fairly establish a shared secret key by using unitary operations and the delayed measurement technique. The security analysis shows that the two protocols can resist against participant attacks and the corresponding outsider attacks. Finally, the comparison with the quantum key agreement protocols immune to collective noise show that the new protocols have higher qubit efficiency.

Key words: quantum cryptography, quantum key agreement, collective noise, qubit efficiency

摘要： 针对目前免疫集体噪声的量子密钥协商协议的量子比特效率偏低问题，基于逻辑Bell态提出了两个新的量子密钥协商协议，它们分别免疫集体退相位噪声和集体旋转噪声。两个协议利用幺正变换和延迟测量技术，确保了协议双方能公平地建立一个共享密钥。安全性分析证明了这两个协议能抵抗参与者攻击和相关外部攻击。与已有免疫集体噪声的量子密钥协商协议比较，发现新协议有较高的量子比特效率。

关键词: 量子密码, 量子密钥协商, 集体噪声, 量子比特效率