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| 1 | +# $Id$ |
| 2 | +# |
| 3 | +# Copyright (C) 2005 Gregory P. Smith (greg@electricrain.com) |
| 4 | +# Licensed to PSF under a Contributor Agreement. |
| 5 | +# |
| 6 | + |
| 7 | +__doc__ = """hashlib module - A common interface to many hash functions. |
| 8 | +
|
| 9 | +new(name, string='') - returns a new hash object implementing the |
| 10 | + given hash function; initializing the hash |
| 11 | + using the given string data. |
| 12 | +
|
| 13 | +Named constructor functions are also available, these are much faster |
| 14 | +than using new(): |
| 15 | +
|
| 16 | +md5(), sha1(), sha224(), sha256(), sha384(), and sha512() |
| 17 | +
|
| 18 | +More algorithms may be available on your platform but the above are |
| 19 | +guaranteed to exist. |
| 20 | +
|
| 21 | +Choose your hash function wisely. Some have known weaknesses. |
| 22 | +sha384 and sha512 will be slow on 32 bit platforms. |
| 23 | +""" |
| 24 | + |
| 25 | + |
| 26 | +def __get_builtin_constructor(name): |
| 27 | + if name in ('SHA1', 'sha1'): |
| 28 | + import _sha |
| 29 | + return _sha.new |
| 30 | + elif name in ('MD5', 'md5'): |
| 31 | + import _md5 |
| 32 | + return _md5.new |
| 33 | + elif name in ('SHA256', 'sha256', 'SHA224', 'sha224'): |
| 34 | + import _sha256 |
| 35 | + bs = name[3:] |
| 36 | + if bs == '256': |
| 37 | + return _sha256.sha256 |
| 38 | + elif bs == '224': |
| 39 | + return _sha256.sha224 |
| 40 | + elif name in ('SHA512', 'sha512', 'SHA384', 'sha384'): |
| 41 | + import _sha512 |
| 42 | + bs = name[3:] |
| 43 | + if bs == '512': |
| 44 | + return _sha512.sha512 |
| 45 | + elif bs == '384': |
| 46 | + return _sha512.sha384 |
| 47 | + |
| 48 | + raise ValueError, "unsupported hash type" |
| 49 | + |
| 50 | + |
| 51 | +def __py_new(name, string=''): |
| 52 | + """new(name, string='') - Return a new hashing object using the named algorithm; |
| 53 | + optionally initialized with a string. |
| 54 | + """ |
| 55 | + return __get_builtin_constructor(name)(string) |
| 56 | + |
| 57 | + |
| 58 | +def __hash_new(name, string=''): |
| 59 | + """new(name, string='') - Return a new hashing object using the named algorithm; |
| 60 | + optionally initialized with a string. |
| 61 | + """ |
| 62 | + try: |
| 63 | + return _hashlib.new(name, string) |
| 64 | + except ValueError: |
| 65 | + # If the _hashlib module (OpenSSL) doesn't support the named |
| 66 | + # hash, try using our builtin implementations. |
| 67 | + # This allows for SHA224/256 and SHA384/512 support even though |
| 68 | + # the OpenSSL library prior to 0.9.8 doesn't provide them. |
| 69 | + return __get_builtin_constructor(name)(string) |
| 70 | + |
| 71 | + |
| 72 | +try: |
| 73 | + import _hashlib |
| 74 | + # use the wrapper of the C implementation |
| 75 | + new = __hash_new |
| 76 | + |
| 77 | + for opensslFuncName in filter(lambda n: n.startswith('openssl_'), dir(_hashlib)): |
| 78 | + funcName = opensslFuncName[len('openssl_'):] |
| 79 | + try: |
| 80 | + # try them all, some may not work due to the OpenSSL |
| 81 | + # version not supporting that algorithm. |
| 82 | + f = getattr(_hashlib, opensslFuncName) |
| 83 | + f() |
| 84 | + # Use the C function directly (very fast) |
| 85 | + exec funcName + ' = f' |
| 86 | + except ValueError: |
| 87 | + try: |
| 88 | + # Use the builtin implementation directly (fast) |
| 89 | + exec funcName + ' = __get_builtin_constructor(funcName)' |
| 90 | + except ValueError: |
| 91 | + # this one has no builtin implementation, don't define it |
| 92 | + pass |
| 93 | + # clean up our locals |
| 94 | + del f |
| 95 | + del opensslFuncName |
| 96 | + del funcName |
| 97 | + |
| 98 | +except ImportError: |
| 99 | + # We don't have the _hashlib OpenSSL module? |
| 100 | + # use the built in legacy interfaces via a wrapper function |
| 101 | + new = __py_new |
| 102 | + |
| 103 | + # lookup the C function to use directly for the named constructors |
| 104 | + md5 = __get_builtin_constructor('md5') |
| 105 | + sha1 = __get_builtin_constructor('sha1') |
| 106 | + sha224 = __get_builtin_constructor('sha224') |
| 107 | + sha256 = __get_builtin_constructor('sha256') |
| 108 | + sha384 = __get_builtin_constructor('sha384') |
| 109 | + sha512 = __get_builtin_constructor('sha512') |
| 110 | + |
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