Edit: hashlib.py
#. Copyright (C) 2005-2010 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, data=b'', **kwargs) - returns a new hash object implementing the given hash function; initializing the hash using the given binary data. Named constructor functions are also available, these are faster than using new(name): md5(), sha1(), sha224(), sha256(), sha384(), sha512(), blake2b(), blake2s(), sha3_224, sha3_256, sha3_384, sha3_512, shake_128, and shake_256. 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(data): Update the hash object with the bytes in data. Repeated calls are equivalent to a single call with the concatenation of all the arguments. - digest(): Return the digest of the bytes passed to the update() method so far as a bytes object. - 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 datas that share a common initial substring. For example, to obtain the digest of the byte string 'Nobody inspects the spammish repetition': >>> import hashlib >>> m = hashlib.md5() >>> m.update(b"Nobody inspects") >>> m.update(b" the spammish repetition") >>> m.digest() b'\\xbbd\\x9c\\x83\\xdd\\x1e\\xa5\\xc9\\xd9\\xde\\xc9\\xa1\\x8d\\xf0\\xff\\xe9' More condensed: >>> hashlib.sha224(b"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', 'blake2b', 'blake2s', 'sha3_224', 'sha3_256', 'sha3_384', 'sha3_512', 'shake_128', 'shake_256') algorithms_guaranteed = set(__always_supported) algorithms_available = set(__always_supported) __all__ = __always_supported + ('new', 'algorithms_guaranteed', 'algorithms_available', 'pbkdf2_hmac') try: from _hashlib import get_fips_mode as _hashlib_get_fips_mode except ImportError: def _hashlib_get_fips_mode(): return 0 if not _hashlib_get_fips_mode(): __builtin_constructor_cache = {} def __get_builtin_constructor(name): cache = __builtin_constructor_cache constructor = cache.get(name) if constructor is not None: return constructor try: if name in ('SHA1', 'sha1'): import _sha1 cache['SHA1'] = cache['sha1'] = _sha1.sha1 elif name in ('MD5', 'md5'): import _md5 cache['MD5'] = cache['md5'] = _md5.md5 elif name in ('SHA256', 'sha256', 'SHA224', 'sha224'): import _sha256 cache['SHA224'] = cache['sha224'] = _sha256.sha224 cache['SHA256'] = cache['sha256'] = _sha256.sha256 elif name in ('SHA512', 'sha512', 'SHA384', 'sha384'): import _sha512 cache['SHA384'] = cache['sha384'] = _sha512.sha384 cache['SHA512'] = cache['sha512'] = _sha512.sha512 elif name in ('blake2b', 'blake2s'): import _blake2 cache['blake2b'] = _blake2.blake2b cache['blake2s'] = _blake2.blake2s elif name in {'sha3_224', 'sha3_256', 'sha3_384', 'sha3_512', 'shake_128', 'shake_256'}: import _sha3 cache['sha3_224'] = _sha3.sha3_224 cache['sha3_256'] = _sha3.sha3_256 cache['sha3_384'] = _sha3.sha3_384 cache['sha3_512'] = _sha3.sha3_512 cache['shake_128'] = _sha3.shake_128 cache['shake_256'] = _sha3.shake_256 except ImportError: pass # no extension module, this hash is unsupported. constructor = cache.get(name) if constructor is not None: return constructor raise ValueError('unsupported hash type ' + name) def __get_openssl_constructor(name): if not _hashlib.get_fips_mode(): if name in { 'blake2b', 'blake2s', 'shake_256', 'shake_128', #'sha3_224', 'sha3_256', 'sha3_384', 'sha3_512', }: # Prefer our blake2 implementation. return __get_builtin_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. if not _hashlib.get_fips_mode(): # N.B. In "FIPS mode", there is no fallback. # If this test fails, we want to export the broken hash # constructor anyway. f() # Use the C function directly (very fast) return f except (AttributeError, ValueError): return __get_builtin_constructor(name) if not _hashlib_get_fips_mode(): def __py_new(name, data=b'', **kwargs): """new(name, data=b'', **kwargs) - Return a new hashing object using the named algorithm; optionally initialized with data (which must be a bytes-like object). """ return __get_builtin_constructor(name)(data, **kwargs) def __hash_new(name, data=b'', **kwargs): """new(name, data=b'') - Return a new hashing object using the named algorithm; optionally initialized with data (which must be a bytes-like object). """ if _hashlib.get_fips_mode(): # Use OpenSSL names for Python built-in hashes orig_name = name name = { 'sha3_224': "sha3-224", 'sha3_256': "sha3-256", 'sha3_384': "sha3-384", 'sha3_512': "sha3-512", 'shake_128': "shake128", 'shake_256': "shake256", }.get(name, name) else: if name in {'blake2b', 'blake2s'}: # Prefer our blake2 implementation. # OpenSSL 1.1.0 comes with a limited implementation of blake2b/s. # It does neither support keyed blake2 nor advanced features like # salt, personal, tree hashing or SSE. return __get_builtin_constructor(name)(data, **kwargs) try: usedforsecurity = kwargs.pop('usedforsecurity', True) retval = _hashlib.new( name, data, usedforsecurity=usedforsecurity) if _hashlib.get_fips_mode() and name != orig_name: retval._set_name(orig_name) return retval 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. if _hashlib.get_fips_mode(): raise return __get_builtin_constructor(name)(data) try: import _hashlib new = __hash_new __get_hash = __get_openssl_constructor algorithms_available = algorithms_available.union( _hashlib.openssl_md_meth_names) except ImportError: if _hashlib_get_fips_mode(): raise new = __py_new __get_hash = __get_builtin_constructor # OpenSSL's PKCS5_PBKDF2_HMAC requires OpenSSL 1.0+ with HMAC and SHA from _hashlib import pbkdf2_hmac try: # OpenSSL's scrypt requires OpenSSL 1.1+ from _hashlib import scrypt except ImportError: pass 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) # Cleanup locals() del __always_supported, __func_name, __get_hash del __hash_new, __get_openssl_constructor if not _hashlib.get_fips_mode(): del __py_new del _hashlib_get_fips_mode
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