SHA-1(Secure Hash Algorithm)是美国国家标准局(National Institute of Standard and Technology NIST)为了配合数位签章演算法(Digital Signature Algorithm DSA)的使用所发布的联邦资讯处理标准-FIPS PUB 180-1(Federal Information Processing Standard Publication 180-1),而SHA-1 则是SHA-1 (FIPS180)的改良版