The DES (Data Encryption Standard) algorithm is the most widely used encryption algorithm in the world. The Data Encryption Standard (DES) specifies a FIPS approved cryptographic algorithm as required by FIPS 140-1. Developed in the 1970s by the Nati

SHA (Secure Hash Algorithm，译作安全散列算法) 是美国国家安全局 (NSA) 设计，美国国家标准与技术研究院 (NIST) 发布的一系列密码散列函数。正式名称为 SHA 的家族第一个成员发布于 1993年。然而现在的人们给它取了一个非正式的名称 SHA-0 以避免与它的后继者混淆。两年之后， SHA-1，第一个 SHA 的后继者发布了。 另外还有四种变体，曾经发布以提升输出的范围和变更一些细微设计: SHA-224, SHA-256, SHA-384 和 SHA-512

In cryptography, SHA-1 is a cryptographic hash function designed by the United States National Security Agency and published by the United States NIST as a U.S. Federal Information Processing Standard. SHA stands for "secure hash algorithm".

sgu261：Discrete Roots(原根+离散对数+扩展欧几里得) 题目大意： 给你两个质数p,k，和整数a(0≤a<p)，求解所有满足x^k≡a(mod p)的x。-261. Discrete Roots time limit per test: 1 sec. memory limit per test: 65536 KB input: standard output: standard There are a lot of