The development of deep learning technology has promoted the wide application of face recognition in many scenarios such as mobile payment and social media, but the security of user data is facing great challenges. To protect the privacy of users, face authentication cannot be operated in plaintext. To solve this problem, a face feature ciphertext authentication scheme based on homomorphic encryption is proposed. First, the face image feature extraction is completed based on a deep learning model. Second, the face features are packaged into ciphertext by using homomorphic encryption and batch processing technology, and the face feature ciphertext is saved in the database of the cloud server. Third, combined with automorphism mapping and Hamming distance, a face feature ciphertext recognition method is designed, which can complete face recognition in the case of ciphertext. Finally, the integrity and consistency of face feature ciphertext recognition results before and after decryption are guaranteed by the one-time MAC authentication method. The whole framework can finish identity recognition without decrypting face feature coding, and the homomorphic ciphertext of face feature coding is saved in the database, so there is no risk of face feature coding leakage. Experiments show that the system has met the requirements of real application scenarios.

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Rapid development of wireless communication technology makes our life convenient. However, it causes two issues: one is shortage of spectrum resources leads to the waste of allocated spectrum resources; the other is wireless communication standards are incompatible. Those two issues can be solved by cognitive radio networks. In this paper, current state of cognitive radio networks is discussed detailed and future network architecture is studied. 【摘要】无线通信技术的快速发展给用户的生活带来便利。但同时也引发了两类问题：其一，频谱资源越来 越短缺，已经分配的频谱资源存在浪费。其二：无线通信的标准繁杂，并且这些标准之间互不兼容。认知 无线电、认知无线网络针对以上问题提出了相应的解决方案。本文详细探讨了认知无线电、认知无线网络 的发展现状，并针对其特点研究了未来网络的体系结构。 【关键词】认知无线电；认知无线网络；网络体系结构 1 引言 无线业务的快速发展和固定频谱分配方式造成了可 用频谱资源的日渐稀少，其弊端越来越明显。根据统计， 在某些热点业务区间，频段变的相当拥挤，频谱资源供不 应求，而在其他的一些频段，则存在大量的闲置。根据 FCC 的调查报告： 美国 30MHz~30GHz 频段之间的平均频 谱使用率仅仅为 5%，而授权频段在 90%的时间内都是空 闲的，综合来看，现有的各频段平均使用率低于 10%。我 国一些地区也有类似的统计数据，比如西安电子科技大学 的统计显示，在西安地区，90%的已划分频谱处于空闲状 态。造成这些问题的原因主要包括一下几个方面： 1)频谱的划分存在保护区域，即两个相邻频段之间 会预留一些区域防止干扰发生，这些区域在通信过程中未 被利用，属于空白区域。 2)部分数据通信属于按需通信，在有通信需求时才 使用资源，没有通信需求时会释放无线资源； 3)有些频段早期已经颁布给某些模拟通信方式，而 随着数字通信技术的发展，先前的模拟通信方式由于其效 率低下已经过时，面临着被更先进的技术所取代而处于被 淘汰的边缘，导致频谱的空闲； 4)与用户使用习惯和位置有关。在夜间用户较少或 者在偏远地区，频谱的利用比人口密集区域低很多。 由此可以看出，现阶段无线通信技术在飞速发展，一 方面频谱资源越来越短缺，另一方面已经分配的频谱资源 978-1-4244-7255-0/11/$26.00 ©2011 IEEE