In 1994, the National Institute of Standards and Technology (NIST) issued a Federal Information Processing Standard for digital signatures, known as the DSA or DSS. The DSS specifies that a DSA should be used in the computing and verifying of digital signatures. Essentially, the DSA helps to verify that data has not been changed after it is signed, thus providing message integrity.
National Institute of Standards and Technology. Fact Sheet on Digital Signature Standard. [Online, 1994.] National Institute of Standards and Technology Website. http://www.nist.gov/public_affairs/releases/digsigst.htm.