/usr/share/pyshared/Crypto/Hash/HMAC.py is in python-crypto 2.4.1-1.
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 | # HMAC.py - Implements the HMAC algorithm as described by RFC 2104.
#
# ===================================================================
# Portions Copyright (c) 2001, 2002, 2003 Python Software Foundation;
# All Rights Reserved
#
# This file contains code from the Python 2.2 hmac.py module (the
# "Original Code"), with modifications made after it was incorporated
# into PyCrypto (the "Modifications").
#
# To the best of our knowledge, the Python Software Foundation is the
# copyright holder of the Original Code, and has licensed it under the
# Python 2.2 license. See the file LEGAL/copy/LICENSE.python-2.2 for
# details.
#
# The Modifications to this file are dedicated to the public domain.
# To the extent that dedication to the public domain is not available,
# everyone is granted a worldwide, perpetual, royalty-free,
# non-exclusive license to exercise all rights associated with the
# contents of this file for any purpose whatsoever. No rights are
# reserved.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
# BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
# ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
# CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.
# ===================================================================
"""HMAC (Keyed-Hashing for Message Authentication) Python module.
Implements the HMAC algorithm as described by RFC 2104.
This is just a copy of the Python 2.2 HMAC module, modified to work when
used on versions of Python before 2.2.
"""
__revision__ = "$Id$"
__all__ = ['new', 'digest_size']
from Crypto.Util.strxor import strxor_c
from Crypto.Util.py3compat import *
# The size of the digests returned by HMAC depends on the underlying
# hashing module used.
digest_size = None
class HMAC:
"""RFC2104 HMAC class.
This supports the API for Cryptographic Hash Functions (PEP 247).
"""
def __init__(self, key, msg = None, digestmod = None):
"""Create a new HMAC object.
key: key for the keyed hash object.
msg: Initial input for the hash, if provided.
digestmod: A module supporting PEP 247. Defaults to the md5 module.
"""
if digestmod is None:
import MD5
digestmod = MD5
self.digestmod = digestmod
self.outer = digestmod.new()
self.inner = digestmod.new()
try:
self.digest_size = digestmod.digest_size
except AttributeError:
self.digest_size = len(self.outer.digest())
try:
# The block size is 128 bytes for SHA384 and SHA512 and 64 bytes
# for the others hash function
blocksize = digestmod.block_size
except AttributeError:
blocksize = 64
ipad = 0x36
opad = 0x5C
if len(key) > blocksize:
key = digestmod.new(key).digest()
key = key + bchr(0) * (blocksize - len(key))
self.outer.update(strxor_c(key, opad))
self.inner.update(strxor_c(key, ipad))
if (msg):
self.update(msg)
## def clear(self):
## raise NotImplementedError, "clear() method not available in HMAC."
def update(self, msg):
"""Update this hashing object with the string msg.
"""
self.inner.update(msg)
def copy(self):
"""Return a separate copy of this hashing object.
An update to this copy won't affect the original object.
"""
other = HMAC(b(""))
other.digestmod = self.digestmod
other.inner = self.inner.copy()
other.outer = self.outer.copy()
return other
def digest(self):
"""Return the hash value of this hashing object.
This returns a string containing 8-bit data. The object is
not altered in any way by this function; you can continue
updating the object after calling this function.
"""
h = self.outer.copy()
h.update(self.inner.digest())
return h.digest()
def hexdigest(self):
"""Like digest(), but returns a string of hexadecimal digits instead.
"""
return "".join(["%02x" % bord(x)
for x in tuple(self.digest())])
def new(key, msg = None, digestmod = None):
"""Create a new hashing object and return it.
key: The starting key for the hash.
msg: if available, will immediately be hashed into the object's starting
state.
You can now feed arbitrary strings into the object using its update()
method, and can ask for the hash value at any time by calling its digest()
method.
"""
return HMAC(key, msg, digestmod)
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