HMAC (Keyed-Hashing for Message Authentication) Python module.
Implements the HMAC algorithm as described by RFC 2104.
This is just a copy of the Python 2.2 HMAC module, modified to work when
used on versions of Python before 2.2.
Create a new hashing object and return it.
key: The starting key for the hash.
msg: if available, will immediately be hashed into the object's starting
state.
You can now feed arbitrary strings into the object using its update()
method, and can ask for the hash value at any time by calling its digest()
method.