Gregory P. Smith | f21a5f7 | 2005-08-21 18:45:59 +0000 | [diff] [blame] | 1 | # $Id$ |
| 2 | # |
Gregory P. Smith | f805785 | 2007-09-09 20:25:00 +0000 | [diff] [blame] | 3 | # Copyright (C) 2005 Gregory P. Smith (greg@krypto.org) |
Gregory P. Smith | f21a5f7 | 2005-08-21 18:45:59 +0000 | [diff] [blame] | 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 | |
Benjamin Peterson | 0062d1e | 2014-08-28 09:41:29 -0400 | [diff] [blame] | 18 | More algorithms may be available on your platform but the above are guaranteed |
| 19 | to exist. See the algorithms_guaranteed and algorithms_available attributes |
| 20 | to find out what algorithm names can be passed to new(). |
Gregory P. Smith | f21a5f7 | 2005-08-21 18:45:59 +0000 | [diff] [blame] | 21 | |
Gregory P. Smith | bde4007 | 2008-03-19 01:38:35 +0000 | [diff] [blame] | 22 | NOTE: If you want the adler32 or crc32 hash functions they are available in |
| 23 | the zlib module. |
| 24 | |
Georg Brandl | 7a4e804 | 2006-10-29 18:01:08 +0000 | [diff] [blame] | 25 | Choose your hash function wisely. Some have known collision weaknesses. |
Gregory P. Smith | f21a5f7 | 2005-08-21 18:45:59 +0000 | [diff] [blame] | 26 | sha384 and sha512 will be slow on 32 bit platforms. |
Georg Brandl | 7a4e804 | 2006-10-29 18:01:08 +0000 | [diff] [blame] | 27 | |
| 28 | Hash objects have these methods: |
| 29 | - update(arg): Update the hash object with the string arg. Repeated calls |
| 30 | are equivalent to a single call with the concatenation of all |
| 31 | the arguments. |
| 32 | - digest(): Return the digest of the strings passed to the update() method |
| 33 | so far. This may contain non-ASCII characters, including |
| 34 | NUL bytes. |
| 35 | - hexdigest(): Like digest() except the digest is returned as a string of |
| 36 | double length, containing only hexadecimal digits. |
| 37 | - copy(): Return a copy (clone) of the hash object. This can be used to |
| 38 | efficiently compute the digests of strings that share a common |
| 39 | initial substring. |
| 40 | |
| 41 | For example, to obtain the digest of the string 'Nobody inspects the |
| 42 | spammish repetition': |
| 43 | |
| 44 | >>> import hashlib |
| 45 | >>> m = hashlib.md5() |
| 46 | >>> m.update("Nobody inspects") |
| 47 | >>> m.update(" the spammish repetition") |
| 48 | >>> m.digest() |
Gregory P. Smith | f07e5a9 | 2008-08-31 16:34:18 +0000 | [diff] [blame] | 49 | '\\xbbd\\x9c\\x83\\xdd\\x1e\\xa5\\xc9\\xd9\\xde\\xc9\\xa1\\x8d\\xf0\\xff\\xe9' |
Georg Brandl | 7a4e804 | 2006-10-29 18:01:08 +0000 | [diff] [blame] | 50 | |
| 51 | More condensed: |
| 52 | |
| 53 | >>> hashlib.sha224("Nobody inspects the spammish repetition").hexdigest() |
| 54 | 'a4337bc45a8fc544c03f52dc550cd6e1e87021bc896588bd79e901e2' |
| 55 | |
Gregory P. Smith | f21a5f7 | 2005-08-21 18:45:59 +0000 | [diff] [blame] | 56 | """ |
| 57 | |
Gregory P. Smith | 99954c9 | 2009-08-16 21:54:45 +0000 | [diff] [blame] | 58 | # This tuple and __get_builtin_constructor() must be modified if a new |
| 59 | # always available algorithm is added. |
| 60 | __always_supported = ('md5', 'sha1', 'sha224', 'sha256', 'sha384', 'sha512') |
| 61 | |
Benjamin Peterson | 0062d1e | 2014-08-28 09:41:29 -0400 | [diff] [blame] | 62 | algorithms_guaranteed = set(__always_supported) |
| 63 | algorithms_available = set(__always_supported) |
| 64 | |
Gregory P. Smith | e6390a1 | 2010-03-01 02:01:47 +0000 | [diff] [blame] | 65 | algorithms = __always_supported |
| 66 | |
Benjamin Peterson | 0062d1e | 2014-08-28 09:41:29 -0400 | [diff] [blame] | 67 | __all__ = __always_supported + ('new', 'algorithms_guaranteed', |
| 68 | 'algorithms_available', 'algorithms', |
| 69 | 'pbkdf2_hmac') |
Gregory P. Smith | 99954c9 | 2009-08-16 21:54:45 +0000 | [diff] [blame] | 70 | |
Gregory P. Smith | f21a5f7 | 2005-08-21 18:45:59 +0000 | [diff] [blame] | 71 | |
| 72 | def __get_builtin_constructor(name): |
Gregory P. Smith | fb1d60c | 2011-05-14 15:07:53 -0700 | [diff] [blame] | 73 | try: |
| 74 | if name in ('SHA1', 'sha1'): |
| 75 | import _sha |
| 76 | return _sha.new |
| 77 | elif name in ('MD5', 'md5'): |
| 78 | import _md5 |
| 79 | return _md5.new |
| 80 | elif name in ('SHA256', 'sha256', 'SHA224', 'sha224'): |
| 81 | import _sha256 |
| 82 | bs = name[3:] |
| 83 | if bs == '256': |
| 84 | return _sha256.sha256 |
| 85 | elif bs == '224': |
| 86 | return _sha256.sha224 |
| 87 | elif name in ('SHA512', 'sha512', 'SHA384', 'sha384'): |
| 88 | import _sha512 |
| 89 | bs = name[3:] |
| 90 | if bs == '512': |
| 91 | return _sha512.sha512 |
| 92 | elif bs == '384': |
| 93 | return _sha512.sha384 |
| 94 | except ImportError: |
| 95 | pass # no extension module, this hash is unsupported. |
Gregory P. Smith | f21a5f7 | 2005-08-21 18:45:59 +0000 | [diff] [blame] | 96 | |
Gregory P. Smith | b9e9e0d | 2012-07-21 21:22:16 -0700 | [diff] [blame] | 97 | raise ValueError('unsupported hash type ' + name) |
Gregory P. Smith | 99954c9 | 2009-08-16 21:54:45 +0000 | [diff] [blame] | 98 | |
| 99 | |
| 100 | def __get_openssl_constructor(name): |
| 101 | try: |
| 102 | f = getattr(_hashlib, 'openssl_' + name) |
| 103 | # Allow the C module to raise ValueError. The function will be |
| 104 | # defined but the hash not actually available thanks to OpenSSL. |
| 105 | f() |
| 106 | # Use the C function directly (very fast) |
| 107 | return f |
| 108 | except (AttributeError, ValueError): |
| 109 | return __get_builtin_constructor(name) |
Gregory P. Smith | f21a5f7 | 2005-08-21 18:45:59 +0000 | [diff] [blame] | 110 | |
| 111 | |
| 112 | def __py_new(name, string=''): |
| 113 | """new(name, string='') - Return a new hashing object using the named algorithm; |
| 114 | optionally initialized with a string. |
| 115 | """ |
| 116 | return __get_builtin_constructor(name)(string) |
| 117 | |
| 118 | |
| 119 | def __hash_new(name, string=''): |
| 120 | """new(name, string='') - Return a new hashing object using the named algorithm; |
| 121 | optionally initialized with a string. |
| 122 | """ |
| 123 | try: |
| 124 | return _hashlib.new(name, string) |
| 125 | except ValueError: |
| 126 | # If the _hashlib module (OpenSSL) doesn't support the named |
| 127 | # hash, try using our builtin implementations. |
| 128 | # This allows for SHA224/256 and SHA384/512 support even though |
| 129 | # the OpenSSL library prior to 0.9.8 doesn't provide them. |
| 130 | return __get_builtin_constructor(name)(string) |
| 131 | |
| 132 | |
| 133 | try: |
| 134 | import _hashlib |
Gregory P. Smith | f21a5f7 | 2005-08-21 18:45:59 +0000 | [diff] [blame] | 135 | new = __hash_new |
Gregory P. Smith | 99954c9 | 2009-08-16 21:54:45 +0000 | [diff] [blame] | 136 | __get_hash = __get_openssl_constructor |
Benjamin Peterson | 0062d1e | 2014-08-28 09:41:29 -0400 | [diff] [blame] | 137 | algorithms_available = algorithms_available.union( |
| 138 | _hashlib.openssl_md_meth_names) |
Gregory P. Smith | f21a5f7 | 2005-08-21 18:45:59 +0000 | [diff] [blame] | 139 | except ImportError: |
Gregory P. Smith | f21a5f7 | 2005-08-21 18:45:59 +0000 | [diff] [blame] | 140 | new = __py_new |
Gregory P. Smith | 99954c9 | 2009-08-16 21:54:45 +0000 | [diff] [blame] | 141 | __get_hash = __get_builtin_constructor |
Gregory P. Smith | f21a5f7 | 2005-08-21 18:45:59 +0000 | [diff] [blame] | 142 | |
Gregory P. Smith | 99954c9 | 2009-08-16 21:54:45 +0000 | [diff] [blame] | 143 | for __func_name in __always_supported: |
| 144 | # try them all, some may not work due to the OpenSSL |
| 145 | # version not supporting that algorithm. |
| 146 | try: |
| 147 | globals()[__func_name] = __get_hash(__func_name) |
| 148 | except ValueError: |
| 149 | import logging |
| 150 | logging.exception('code for hash %s was not found.', __func_name) |
| 151 | |
Benjamin Peterson | 48f2e99 | 2014-05-31 13:26:22 -0700 | [diff] [blame] | 152 | |
| 153 | try: |
| 154 | # OpenSSL's PKCS5_PBKDF2_HMAC requires OpenSSL 1.0+ with HMAC and SHA |
| 155 | from _hashlib import pbkdf2_hmac |
| 156 | except ImportError: |
| 157 | import binascii |
| 158 | import struct |
| 159 | |
| 160 | _trans_5C = b"".join(chr(x ^ 0x5C) for x in range(256)) |
| 161 | _trans_36 = b"".join(chr(x ^ 0x36) for x in range(256)) |
| 162 | |
| 163 | def pbkdf2_hmac(hash_name, password, salt, iterations, dklen=None): |
| 164 | """Password based key derivation function 2 (PKCS #5 v2.0) |
| 165 | |
| 166 | This Python implementations based on the hmac module about as fast |
| 167 | as OpenSSL's PKCS5_PBKDF2_HMAC for short passwords and much faster |
| 168 | for long passwords. |
| 169 | """ |
| 170 | if not isinstance(hash_name, str): |
| 171 | raise TypeError(hash_name) |
| 172 | |
| 173 | if not isinstance(password, (bytes, bytearray)): |
| 174 | password = bytes(buffer(password)) |
| 175 | if not isinstance(salt, (bytes, bytearray)): |
| 176 | salt = bytes(buffer(salt)) |
| 177 | |
| 178 | # Fast inline HMAC implementation |
| 179 | inner = new(hash_name) |
| 180 | outer = new(hash_name) |
| 181 | blocksize = getattr(inner, 'block_size', 64) |
| 182 | if len(password) > blocksize: |
| 183 | password = new(hash_name, password).digest() |
| 184 | password = password + b'\x00' * (blocksize - len(password)) |
| 185 | inner.update(password.translate(_trans_36)) |
| 186 | outer.update(password.translate(_trans_5C)) |
| 187 | |
| 188 | def prf(msg, inner=inner, outer=outer): |
| 189 | # PBKDF2_HMAC uses the password as key. We can re-use the same |
Serhiy Storchaka | 0f8f784 | 2014-12-01 18:16:30 +0200 | [diff] [blame] | 190 | # digest objects and just update copies to skip initialization. |
Benjamin Peterson | 48f2e99 | 2014-05-31 13:26:22 -0700 | [diff] [blame] | 191 | icpy = inner.copy() |
| 192 | ocpy = outer.copy() |
| 193 | icpy.update(msg) |
| 194 | ocpy.update(icpy.digest()) |
| 195 | return ocpy.digest() |
| 196 | |
| 197 | if iterations < 1: |
| 198 | raise ValueError(iterations) |
| 199 | if dklen is None: |
| 200 | dklen = outer.digest_size |
| 201 | if dklen < 1: |
| 202 | raise ValueError(dklen) |
| 203 | |
| 204 | hex_format_string = "%%0%ix" % (new(hash_name).digest_size * 2) |
| 205 | |
| 206 | dkey = b'' |
| 207 | loop = 1 |
| 208 | while len(dkey) < dklen: |
| 209 | prev = prf(salt + struct.pack(b'>I', loop)) |
| 210 | rkey = int(binascii.hexlify(prev), 16) |
| 211 | for i in xrange(iterations - 1): |
| 212 | prev = prf(prev) |
| 213 | rkey ^= int(binascii.hexlify(prev), 16) |
| 214 | loop += 1 |
| 215 | dkey += binascii.unhexlify(hex_format_string % rkey) |
| 216 | |
| 217 | return dkey[:dklen] |
| 218 | |
Gregory P. Smith | 99954c9 | 2009-08-16 21:54:45 +0000 | [diff] [blame] | 219 | # Cleanup locals() |
| 220 | del __always_supported, __func_name, __get_hash |
| 221 | del __py_new, __hash_new, __get_openssl_constructor |