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Diffstat (limited to 'Lib/hashlib.py')
-rw-r--r-- | Lib/hashlib.py | 110 |
1 files changed, 110 insertions, 0 deletions
diff --git a/Lib/hashlib.py b/Lib/hashlib.py new file mode 100644 index 0000000..3528699 --- /dev/null +++ b/Lib/hashlib.py @@ -0,0 +1,110 @@ +# $Id$ +# +# Copyright (C) 2005 Gregory P. Smith (greg@electricrain.com) +# 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. + +Choose your hash function wisely. Some have known weaknesses. +sha384 and sha512 will be slow on 32 bit platforms. +""" + + +def __get_builtin_constructor(name): + 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 + + raise ValueError, "unsupported hash type" + + +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 + # use the wrapper of the C implementation + new = __hash_new + + for opensslFuncName in filter(lambda n: n.startswith('openssl_'), dir(_hashlib)): + funcName = opensslFuncName[len('openssl_'):] + try: + # try them all, some may not work due to the OpenSSL + # version not supporting that algorithm. + f = getattr(_hashlib, opensslFuncName) + f() + # Use the C function directly (very fast) + exec funcName + ' = f' + except ValueError: + try: + # Use the builtin implementation directly (fast) + exec funcName + ' = __get_builtin_constructor(funcName)' + except ValueError: + # this one has no builtin implementation, don't define it + pass + # clean up our locals + del f + del opensslFuncName + del funcName + +except ImportError: + # We don't have the _hashlib OpenSSL module? + # use the built in legacy interfaces via a wrapper function + new = __py_new + + # lookup the C function to use directly for the named constructors + md5 = __get_builtin_constructor('md5') + sha1 = __get_builtin_constructor('sha1') + sha224 = __get_builtin_constructor('sha224') + sha256 = __get_builtin_constructor('sha256') + sha384 = __get_builtin_constructor('sha384') + sha512 = __get_builtin_constructor('sha512') + |