``hmac`` --- Keyed-Hashing for Message Authentication ***************************************************** New in version 2.2. This module implements the HMAC algorithm as described by **RFC 2104**. hmac.new(key[, msg[, digestmod]]) Return a new hmac object. If *msg* is present, the method call ``update(msg)`` is made. *digestmod* is the digest constructor or module for the HMAC object to use. It defaults to the ``hashlib.md5()`` constructor. Note: The md5 hash has known weaknesses but remains the default for backwards compatibility. Choose a better one for your application. An HMAC object has the following methods: hmac.update(msg) Update the hmac object with the string *msg*. Repeated calls are equivalent to a single call with the concatenation of all the arguments: ``m.update(a); m.update(b)`` is equivalent to ``m.update(a + b)``. hmac.digest() Return the digest of the strings passed to the ``update()`` method so far. This string will be the same length as the *digest_size* of the digest given to the constructor. It may contain non-ASCII characters, including NUL bytes. hmac.hexdigest() Like ``digest()`` except the digest is returned as a string twice the length containing only hexadecimal digits. This may be used to exchange the value safely in email or other non-binary environments. hmac.copy() Return a copy ("clone") of the hmac object. This can be used to efficiently compute the digests of strings that share a common initial substring. See also: Module ``hashlib`` The python module providing secure hash functions.