Abstract: For protecting the sensitive information in wireless sensor networks，it is essential to encrypt communications.However encryption is problematic since nodes have limited energy，CPU and memory capabilities.To overcome these shortcomings，a new encryption scheme is presented in this paper.It’s called interleaved encryption，which has the form like a chain.And it’s based on the symmetric key cryptosystem.Different from others，the encryption is not between two direct neighbours.Besides making communications more safe，the scheme has less operations of encryption and decryption.

Key words: wireless sensor networks, symmetric key cryptosystem, interleaved encryption, shared key

摘要： 无线传感器网中许多敏感、机密的数据需要加密保护。但受限于网络本身的特点，难以直接应用有线网中现有的安全技术，而需要更加高效的加密方式。在前人的基础上，改进并提出了一种新的加密方案。该方案基于对称密钥密码系统；网络中节点与其每个一、二跳邻节点分别共享一对密钥；传输数据时只用跟二跳邻节点的共享密钥加密，这样就构成了所谓的交叉加密。

关键词: 无线传感器网, 对称加密, 交叉加密, 共享密钥