序列的随机性测试。 SP800是美国NIST（National Institute of Standards and Technology）发布的一系列关于信息安全的指南（SP是Special Publications的缩写）。文档很多，也很细，值得大家学习。在NIST的标准系列文件中，虽然NIST SP并不作为正式法定标准，但在实际工作中，已经成为美国和国际安全界得到广泛认可的事实标准和权威指南。NIST SP800系列（成为了指导美国信息安全管理建设的主要标准和参考资料。(The randomness test of the sequence. SP800 is a series of information security guidelines issued by the US NIST (National Institute of Standards and Technology) (SP is the abbreviation for Special Publications). A lot of documents, and very thin, it is worth learning. In the NIST standard series, although NIST SP is not a formal legal standard, it has become a widely recognized factual and authoritative guide in the actual work of the United States and the international security community. NIST SP800 series has become the main standard and reference material for guiding the construction of information security management in the US.)