Hash函数是提供数据完整性保障的一个重要工具。本次实验，我们希望通过上机操作，使 同学们对安全Hash算法SHA-1的基本原理有一个全面的理解。通过本次实验，使学生掌握对 Hash函数的应用，为后面数字签名方案的学习打下基础。(The Hash function is an important tool for providing data integrity protection. In this experiment, we hope to have a comprehensive understanding of the basic principles of the security Hash algorithm SHA-1 through the operation of the machine. Through this experiment, the students can grasp the application of the Hash function and lay the foundation for the learning of the later digital signature scheme.)