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Tip revision: 74f4bd53e03ded8408bcc2de67cf0f5a4ac5b1a1 authored by Barry Warsaw on 23 February 2012, 15:59:38 UTC
Bump some more copyright years (as per PEP 101), since this is the first
Bump some more copyright years (as per PEP 101), since this is the first
Tip revision: 74f4bd5
hmac.rst
:mod:`hmac` --- Keyed-Hashing for Message Authentication
========================================================
.. module:: hmac
:synopsis: Keyed-Hashing for Message Authentication (HMAC) implementation for Python.
.. moduleauthor:: Gerhard Häring <ghaering@users.sourceforge.net>
.. sectionauthor:: Gerhard Häring <ghaering@users.sourceforge.net>
.. versionadded:: 2.2
This module implements the HMAC algorithm as described by :rfc:`2104`.
.. function:: 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 :func:`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:
.. method:: 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)``.
.. method:: hmac.digest()
Return the digest of the strings passed to the :meth:`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.
.. method:: hmac.hexdigest()
Like :meth:`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.
.. method:: 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.
.. seealso::
Module :mod:`hashlib`
The Python module providing secure hash functions.