This module implements the interface to NIST's secure hash algorithm, known as SHA. It is used in the same way as the md5 module: use the new() to create an sha object, then feed this object with arbitrary strings using the update() method, and at any point you can ask it for the digest of the contatenation of the strings fed to it so far. SHA digests are 160 bits instead of 128 bits.
The following values are provided as constants in the module and as attributes of the sha objects returned by new():
1. This size is used to allow an arbitrary string to be hashed.
A sha object has all the methods the md5 objects have, plus one: