Abstract: Physical-layer channel noise can be used to enhance the security performance of the system in wireless networks. In general, a physical-layer security protocol is tailored to the channels and relies on the assumption that knowledge on the eavesdropper’s channel is available. However, this assumption is not practical. This paper focuses on the problem of developing key agreement schemes for secure communication across wireless channel, and proposes a key evolution scheme and designs an encryption mechanism based on dynamic secrets, allowing the legitimate users’ keys to evolve continuously based on the transmitted messages over the noisy wireless channel without assuming that the channel characteristics of the enemy are known. Even if the eavesdropper’s channel is superior to the legitimate receiver, the legitimate parties can establish secret keys. Finally, this paper proposes a novel k-resistance encryption scheme (k-RES) that can use different keys to encrypt and decrypt messages if there are no more than k bits difference between the encryption and decryption keys.

Key words: dynamic keys, key evolution, physical-layer security, information security

摘要： 无线网络可以利用物理层的信道噪声来增强系统的安全性能。通常物理层安全协议针对特定无线信道的噪声特性进行设计，并假设窃听者的信道特性已知，但在实际中该假设是不可行的。针对无线信道的安全通信问题，提出了密钥进化协议，设计了基于动态秘密的加密机制，使合法用户的密钥随传输数据流不断进化，而不用假设敌手的信道特征已知。如果合法用户之间存在认证信道，即使敌手的信道相比合法用户的信道具有优势，合法用户之间也能建立安全的会话密钥。最后，提出了k容忍加密机制（k-resistance encryption scheme，k-RES），该机制能够容忍加密密钥和解密密钥之间最多k比特的差异。

关键词: 动态密钥, 密钥进化, 物理层安全, 信息安全