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svn+ssh://pythondev@svn.python.org/python/trunk ........ r68450 | jeffrey.yasskin | 2009-01-09 10:47:07 -0600 (Fri, 09 Jan 2009) | 3 lines Fix issue 4884, preventing a crash in the socket code when python is compiled with llvm-gcc and run with a glibc <2.10. ........ r68480 | vinay.sajip | 2009-01-10 07:38:04 -0600 (Sat, 10 Jan 2009) | 1 line Minor documentation changes cross-referencing NullHandler to the documentation on configuring logging in a library. ........ r68481 | vinay.sajip | 2009-01-10 07:42:04 -0600 (Sat, 10 Jan 2009) | 1 line Corrected an incorrect self-reference. ........ r68493 | benjamin.peterson | 2009-01-10 11:18:55 -0600 (Sat, 10 Jan 2009) | 1 line rewrite verbose conditionals ........ r68495 | benjamin.peterson | 2009-01-10 11:36:44 -0600 (Sat, 10 Jan 2009) | 1 line tp_iter only exists with Py_TPFLAGS_HAVE_ITER #4901 ........ r68501 | vinay.sajip | 2009-01-10 13:22:57 -0600 (Sat, 10 Jan 2009) | 1 line Corrected minor typo and added .currentmodule directives to fix missing cross-references. ........ r68512 | benjamin.peterson | 2009-01-10 16:42:10 -0600 (Sat, 10 Jan 2009) | 1 line make tests fail if they can't be imported ........ r68514 | benjamin.peterson | 2009-01-10 17:41:59 -0600 (Sat, 10 Jan 2009) | 1 line move seealso to a more appropiate place ........ r68515 | benjamin.peterson | 2009-01-10 17:49:08 -0600 (Sat, 10 Jan 2009) | 1 line macos 9 isn't supported ........ r68534 | gregory.p.smith | 2009-01-11 11:53:33 -0600 (Sun, 11 Jan 2009) | 2 lines correct email address ........ r68535 | gregory.p.smith | 2009-01-11 11:57:54 -0600 (Sun, 11 Jan 2009) | 9 lines Update the documentation for binascii and zlib crc32/adler32 functions to better describe the signed vs unsigned return value behavior on different platforms and versions of python. Mention the workaround to make them all return the same thing by using & 0xffffffff. Fixes issue4903. Also needs to be merged into release26-maint, release30-maint, & py3k. ........ r68536 | benjamin.peterson | 2009-01-11 13:48:15 -0600 (Sun, 11 Jan 2009) | 1 line add email addresses ........ r68552 | vinay.sajip | 2009-01-12 14:36:18 -0600 (Mon, 12 Jan 2009) | 1 line Minor changes/corrections in markup. ........ r68563 | benjamin.peterson | 2009-01-12 19:49:10 -0600 (Mon, 12 Jan 2009) | 1 line small logic correction ........ r68570 | raymond.hettinger | 2009-01-13 03:08:32 -0600 (Tue, 13 Jan 2009) | 5 lines Issue 4922: Incorrect comments for MutableSet.add() and MutableSet.discard(). Needs to be backported to 2.6 and forward ported to 3.0 and 3.1. ........ r68571 | armin.ronacher | 2009-01-13 05:52:23 -0600 (Tue, 13 Jan 2009) | 3 lines ast.literal_eval can properly evaluate complex numbers now. This fixes issue4907. ........ r68572 | andrew.kuchling | 2009-01-13 07:40:54 -0600 (Tue, 13 Jan 2009) | 1 line Note that first coord. is left alone ........ r68575 | thomas.heller | 2009-01-13 11:32:28 -0600 (Tue, 13 Jan 2009) | 1 line Fix refcount leak in error cases. Bug found by coverity. ........ r68582 | georg.brandl | 2009-01-13 16:14:01 -0600 (Tue, 13 Jan 2009) | 2 lines Use assertRaises. ........ r68596 | amaury.forgeotdarc | 2009-01-13 17:39:22 -0600 (Tue, 13 Jan 2009) | 3 lines #1162154: inspect.getmembers() now skips attributes that raise AttributeError, e.g. a __slots__ attribute which has not been set. ........ r68623 | vinay.sajip | 2009-01-15 16:48:13 -0600 (Thu, 15 Jan 2009) | 1 line Made minor changes/corrections in markup. Added a couple of section headings. ........ r68624 | vinay.sajip | 2009-01-15 17:04:47 -0600 (Thu, 15 Jan 2009) | 1 line Minor changes/corrections in markup. ........ r68628 | benjamin.peterson | 2009-01-15 20:55:24 -0600 (Thu, 15 Jan 2009) | 1 line compare with == not is #4946 ........
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4.9 KiB
ReStructuredText
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:mod:`hashlib` --- Secure hashes and message digests
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====================================================
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.. module:: hashlib
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:synopsis: Secure hash and message digest algorithms.
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.. moduleauthor:: Gregory P. Smith <greg@krypto.org>
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.. sectionauthor:: Gregory P. Smith <greg@krypto.org>
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.. index::
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single: message digest, MD5
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single: secure hash algorithm, SHA1, SHA224, SHA256, SHA384, SHA512
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This module implements a common interface to many different secure hash and
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message digest algorithms. Included are the FIPS secure hash algorithms SHA1,
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SHA224, SHA256, SHA384, and SHA512 (defined in FIPS 180-2) as well as RSA's MD5
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algorithm (defined in Internet :rfc:`1321`). The terms "secure hash" and
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"message digest" are interchangeable. Older algorithms were called message
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digests. The modern term is secure hash.
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.. note::
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If you want the adler32 or crc32 hash functions they are available in
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the :mod:`zlib` module.
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.. warning::
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Some algorithms have known hash collision weaknesses, see the FAQ at the end.
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There is one constructor method named for each type of :dfn:`hash`. All return
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a hash object with the same simple interface. For example: use :func:`sha1` to
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create a SHA1 hash object. You can now feed this object with objects conforming
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to the buffer interface (normally :class:`bytes` objects) using the
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:meth:`update` method. At any point you can ask it for the :dfn:`digest` of the
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concatenation of the data fed to it so far using the :meth:`digest` or
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:meth:`hexdigest` methods.
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.. note::
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For better multithreading performance, the Python GIL is released for
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strings of more than 2047 bytes at object creation or on update.
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.. note::
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Feeding string objects is to :meth:`update` is not supported, as hashes work
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on bytes, not on characters.
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.. index:: single: OpenSSL; (use in module hashlib)
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Constructors for hash algorithms that are always present in this module are
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:func:`md5`, :func:`sha1`, :func:`sha224`, :func:`sha256`, :func:`sha384`, and
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:func:`sha512`. Additional algorithms may also be available depending upon the
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OpenSSL library that Python uses on your platform.
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For example, to obtain the digest of the byte string ``b'Nobody inspects the
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spammish repetition'``::
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>>> import hashlib
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>>> m = hashlib.md5()
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>>> m.update(b"Nobody inspects")
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>>> m.update(b" the spammish repetition")
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>>> m.digest()
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b'\xbbd\x9c\x83\xdd\x1e\xa5\xc9\xd9\xde\xc9\xa1\x8d\xf0\xff\xe9'
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>>> m.digest_size
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16
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>>> m.block_size
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64
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More condensed:
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>>> hashlib.sha224(b"Nobody inspects the spammish repetition").hexdigest()
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'a4337bc45a8fc544c03f52dc550cd6e1e87021bc896588bd79e901e2'
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A generic :func:`new` constructor that takes the string name of the desired
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algorithm as its first parameter also exists to allow access to the above listed
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hashes as well as any other algorithms that your OpenSSL library may offer. The
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named constructors are much faster than :func:`new` and should be preferred.
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Using :func:`new` with an algorithm provided by OpenSSL:
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>>> h = hashlib.new('ripemd160')
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>>> h.update(b"Nobody inspects the spammish repetition")
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>>> h.hexdigest()
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'cc4a5ce1b3df48aec5d22d1f16b894a0b894eccc'
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The following values are provided as constant attributes of the hash objects
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returned by the constructors:
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.. data:: digest_size
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The size of the resulting hash in bytes.
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.. data:: block_size
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The internal block size of the hash algorithm in bytes.
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A hash object has the following methods:
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.. method:: hash.update(arg)
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Update the hash object with the object *arg*, which must be interpretable as
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a buffer of bytes. Repeated calls are equivalent to a single call with the
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concatenation of all the arguments: ``m.update(a); m.update(b)`` is
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equivalent to ``m.update(a+b)``.
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.. method:: hash.digest()
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Return the digest of the data passed to the :meth:`update` method so far.
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This is a bytes array of size :attr:`digest_size` which may contain bytes in
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the whole range from 0 to 255.
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.. method:: hash.hexdigest()
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Like :meth:`digest` except the digest is returned as a string object of
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double length, containing only hexadecimal digits. This may be used to
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exchange the value safely in email or other non-binary environments.
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.. method:: hash.copy()
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Return a copy ("clone") of the hash object. This can be used to efficiently
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compute the digests of data sharing a common initial substring.
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.. seealso::
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Module :mod:`hmac`
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A module to generate message authentication codes using hashes.
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Module :mod:`base64`
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Another way to encode binary hashes for non-binary environments.
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http://csrc.nist.gov/publications/fips/fips180-2/fips180-2.pdf
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The FIPS 180-2 publication on Secure Hash Algorithms.
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http://www.cryptography.com/cnews/hash.html
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Hash Collision FAQ with information on which algorithms have known issues and
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what that means regarding their use.
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