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Diffstat (limited to 'lib/python2.7/hashlib.py')
| -rw-r--r-- | lib/python2.7/hashlib.py | 221 |
1 files changed, 221 insertions, 0 deletions
diff --git a/lib/python2.7/hashlib.py b/lib/python2.7/hashlib.py new file mode 100644 index 0000000..bbd06b9 --- /dev/null +++ b/lib/python2.7/hashlib.py @@ -0,0 +1,221 @@ +# $Id$ +# +# Copyright (C) 2005 Gregory P. Smith (greg@krypto.org) +# Licensed to PSF under a Contributor Agreement. +# + +__doc__ = """hashlib module - A common interface to many hash functions. + +new(name, string='') - returns a new hash object implementing the + given hash function; initializing the hash + using the given string data. + +Named constructor functions are also available, these are much faster +than using new(): + +md5(), sha1(), sha224(), sha256(), sha384(), and sha512() + +More algorithms may be available on your platform but the above are guaranteed +to exist. See the algorithms_guaranteed and algorithms_available attributes +to find out what algorithm names can be passed to new(). + +NOTE: If you want the adler32 or crc32 hash functions they are available in +the zlib module. + +Choose your hash function wisely. Some have known collision weaknesses. +sha384 and sha512 will be slow on 32 bit platforms. + +Hash objects have these methods: + - update(arg): Update the hash object with the string arg. Repeated calls + are equivalent to a single call with the concatenation of all + the arguments. + - digest(): Return the digest of the strings passed to the update() method + so far. This may contain non-ASCII characters, including + NUL bytes. + - hexdigest(): Like digest() except the digest is returned as a string of + double length, containing only hexadecimal digits. + - copy(): Return a copy (clone) of the hash object. This can be used to + efficiently compute the digests of strings that share a common + initial substring. + +For example, to obtain the digest of the string 'Nobody inspects the +spammish repetition': + + >>> import hashlib + >>> m = hashlib.md5() + >>> m.update("Nobody inspects") + >>> m.update(" the spammish repetition") + >>> m.digest() + '\\xbbd\\x9c\\x83\\xdd\\x1e\\xa5\\xc9\\xd9\\xde\\xc9\\xa1\\x8d\\xf0\\xff\\xe9' + +More condensed: + + >>> hashlib.sha224("Nobody inspects the spammish repetition").hexdigest() + 'a4337bc45a8fc544c03f52dc550cd6e1e87021bc896588bd79e901e2' + +""" + +# This tuple and __get_builtin_constructor() must be modified if a new +# always available algorithm is added. +__always_supported = ('md5', 'sha1', 'sha224', 'sha256', 'sha384', 'sha512') + +algorithms_guaranteed = set(__always_supported) +algorithms_available = set(__always_supported) + +algorithms = __always_supported + +__all__ = __always_supported + ('new', 'algorithms_guaranteed', + 'algorithms_available', 'algorithms', + 'pbkdf2_hmac') + + +def __get_builtin_constructor(name): + try: + if name in ('SHA1', 'sha1'): + import _sha + return _sha.new + elif name in ('MD5', 'md5'): + import _md5 + return _md5.new + elif name in ('SHA256', 'sha256', 'SHA224', 'sha224'): + import _sha256 + bs = name[3:] + if bs == '256': + return _sha256.sha256 + elif bs == '224': + return _sha256.sha224 + elif name in ('SHA512', 'sha512', 'SHA384', 'sha384'): + import _sha512 + bs = name[3:] + if bs == '512': + return _sha512.sha512 + elif bs == '384': + return _sha512.sha384 + except ImportError: + pass # no extension module, this hash is unsupported. + + raise ValueError('unsupported hash type ' + name) + + +def __get_openssl_constructor(name): + try: + f = getattr(_hashlib, 'openssl_' + name) + # Allow the C module to raise ValueError. The function will be + # defined but the hash not actually available thanks to OpenSSL. + f() + # Use the C function directly (very fast) + return f + except (AttributeError, ValueError): + return __get_builtin_constructor(name) + + +def __py_new(name, string=''): + """new(name, string='') - Return a new hashing object using the named algorithm; + optionally initialized with a string. + """ + return __get_builtin_constructor(name)(string) + + +def __hash_new(name, string=''): + """new(name, string='') - Return a new hashing object using the named algorithm; + optionally initialized with a string. + """ + try: + return _hashlib.new(name, string) + except ValueError: + # If the _hashlib module (OpenSSL) doesn't support the named + # hash, try using our builtin implementations. + # This allows for SHA224/256 and SHA384/512 support even though + # the OpenSSL library prior to 0.9.8 doesn't provide them. + return __get_builtin_constructor(name)(string) + + +try: + import _hashlib + new = __hash_new + __get_hash = __get_openssl_constructor + algorithms_available = algorithms_available.union( + _hashlib.openssl_md_meth_names) +except ImportError: + new = __py_new + __get_hash = __get_builtin_constructor + +for __func_name in __always_supported: + # try them all, some may not work due to the OpenSSL + # version not supporting that algorithm. + try: + globals()[__func_name] = __get_hash(__func_name) + except ValueError: + import logging + logging.exception('code for hash %s was not found.', __func_name) + + +try: + # OpenSSL's PKCS5_PBKDF2_HMAC requires OpenSSL 1.0+ with HMAC and SHA + from _hashlib import pbkdf2_hmac +except ImportError: + import binascii + import struct + + _trans_5C = b"".join(chr(x ^ 0x5C) for x in range(256)) + _trans_36 = b"".join(chr(x ^ 0x36) for x in range(256)) + + def pbkdf2_hmac(hash_name, password, salt, iterations, dklen=None): + """Password based key derivation function 2 (PKCS #5 v2.0) + + This Python implementations based on the hmac module about as fast + as OpenSSL's PKCS5_PBKDF2_HMAC for short passwords and much faster + for long passwords. + """ + if not isinstance(hash_name, str): + raise TypeError(hash_name) + + if not isinstance(password, (bytes, bytearray)): + password = bytes(buffer(password)) + if not isinstance(salt, (bytes, bytearray)): + salt = bytes(buffer(salt)) + + # Fast inline HMAC implementation + inner = new(hash_name) + outer = new(hash_name) + blocksize = getattr(inner, 'block_size', 64) + if len(password) > blocksize: + password = new(hash_name, password).digest() + password = password + b'\x00' * (blocksize - len(password)) + inner.update(password.translate(_trans_36)) + outer.update(password.translate(_trans_5C)) + + def prf(msg, inner=inner, outer=outer): + # PBKDF2_HMAC uses the password as key. We can re-use the same + # digest objects and just update copies to skip initialization. + icpy = inner.copy() + ocpy = outer.copy() + icpy.update(msg) + ocpy.update(icpy.digest()) + return ocpy.digest() + + if iterations < 1: + raise ValueError(iterations) + if dklen is None: + dklen = outer.digest_size + if dklen < 1: + raise ValueError(dklen) + + hex_format_string = "%%0%ix" % (new(hash_name).digest_size * 2) + + dkey = b'' + loop = 1 + while len(dkey) < dklen: + prev = prf(salt + struct.pack(b'>I', loop)) + rkey = int(binascii.hexlify(prev), 16) + for i in xrange(iterations - 1): + prev = prf(prev) + rkey ^= int(binascii.hexlify(prev), 16) + loop += 1 + dkey += binascii.unhexlify(hex_format_string % rkey) + + return dkey[:dklen] + +# Cleanup locals() +del __always_supported, __func_name, __get_hash +del __py_new, __hash_new, __get_openssl_constructor |