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2f21eb3a15
when the OpenSSL library is either not present or not found by setup.py. These are derived from the public domain libtomcrypt (libtom.org) just like the existing sha256 and sha512 modules.
138 lines
4.7 KiB
Python
138 lines
4.7 KiB
Python
# $Id$
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#
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# Copyright (C) 2005-2007 Gregory P. Smith (greg@krypto.org)
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# Licensed to PSF under a Contributor Agreement.
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#
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__doc__ = """hashlib module - A common interface to many hash functions.
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new(name, data=b'') - returns a new hash object implementing the
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given hash function; initializing the hash
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using the given binary data.
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Named constructor functions are also available, these are faster
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than using new(name):
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md5(), sha1(), sha224(), sha256(), sha384(), and sha512()
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More algorithms may be available on your platform but the above are
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guaranteed to exist.
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Choose your hash function wisely. Some have known collision weaknesses.
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sha384 and sha512 will be slow on 32 bit platforms.
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Hash objects have these methods:
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- update(arg): Update the hash object with the bytes in arg. Repeated calls
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are equivalent to a single call with the concatenation of all
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the arguments.
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- digest(): Return the digest of the bytes passed to the update() method
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so far.
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- hexdigest(): Like digest() except the digest is returned as a unicode
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object of double length, containing only hexadecimal digits.
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- copy(): Return a copy (clone) of the hash object. This can be used to
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efficiently compute the digests of strings that share a common
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initial substring.
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For example, to obtain the digest of the string '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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More condensed:
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>>> hashlib.sha224(b"Nobody inspects the spammish repetition").hexdigest()
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'a4337bc45a8fc544c03f52dc550cd6e1e87021bc896588bd79e901e2'
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"""
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def __get_builtin_constructor(name):
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if name in ('SHA1', 'sha1'):
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import _sha1
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return _sha1.sha1
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elif name in ('MD5', 'md5'):
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import _md5
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return _md5.md5
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elif name in ('SHA256', 'sha256', 'SHA224', 'sha224'):
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import _sha256
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bs = name[3:]
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if bs == '256':
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return _sha256.sha256
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elif bs == '224':
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return _sha256.sha224
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elif name in ('SHA512', 'sha512', 'SHA384', 'sha384'):
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import _sha512
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bs = name[3:]
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if bs == '512':
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return _sha512.sha512
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elif bs == '384':
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return _sha512.sha384
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raise ValueError("unsupported hash type")
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def __py_new(name, data=b''):
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"""new(name, data=b'') - Return a new hashing object using the named algorithm;
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optionally initialized with data (which must be bytes).
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"""
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return __get_builtin_constructor(name)(data)
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def __hash_new(name, data=b''):
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"""new(name, data=b'') - Return a new hashing object using the named algorithm;
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optionally initialized with data (which must be bytes).
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"""
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try:
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return _hashlib.new(name, data)
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except ValueError:
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# If the _hashlib module (OpenSSL) doesn't support the named
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# hash, try using our builtin implementations.
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# This allows for SHA224/256 and SHA384/512 support even though
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# the OpenSSL library prior to 0.9.8 doesn't provide them.
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return __get_builtin_constructor(name)(data)
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try:
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import _hashlib
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# use the wrapper of the C implementation
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new = __hash_new
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for opensslFuncName in filter(lambda n: n.startswith('openssl_'), dir(_hashlib)):
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funcName = opensslFuncName[len('openssl_'):]
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try:
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# try them all, some may not work due to the OpenSSL
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# version not supporting that algorithm.
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f = getattr(_hashlib, opensslFuncName)
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f()
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# Use the C function directly (very fast)
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exec(funcName + ' = f')
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except ValueError:
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try:
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# Use the builtin implementation directly (fast)
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exec(funcName + ' = __get_builtin_constructor(funcName)')
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except ValueError:
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# this one has no builtin implementation, don't define it
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pass
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# clean up our locals
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del f
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del opensslFuncName
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del funcName
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except ImportError:
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# We don't have the _hashlib OpenSSL module?
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# use the built in legacy interfaces via a wrapper function
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new = __py_new
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# lookup the C function to use directly for the named constructors
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md5 = __get_builtin_constructor('md5')
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sha1 = __get_builtin_constructor('sha1')
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sha224 = __get_builtin_constructor('sha224')
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sha256 = __get_builtin_constructor('sha256')
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sha384 = __get_builtin_constructor('sha384')
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sha512 = __get_builtin_constructor('sha512')
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