The Digest::SHA1 module allows you to use the NIST SHA-1 message digest algorithm from within Perl programs. The algorithm takes as input a message of arbitrary length and produces as output a 160-bit "fingerprint" or "message digest" of the input.

The Digest::SHA1 module provide a procedural interface for simple use, as well as an object oriented interface that can handle messages of arbitrary length and which can read files directly.

A binary digest will be 20 bytes long. A hex digest will be 40 characters long. A base64 digest will be 27 characters long.