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Merged revisions 58862-58885 via svnmerge from
svn+ssh://pythondev@svn.python.org/python/trunk ........ r58868 | gregory.p.smith | 2007-11-05 16:19:03 -0800 (Mon, 05 Nov 2007) | 3 lines Fixes Issue 1385: The hmac module now computes the correct hmac when using hashes with a block size other than 64 bytes (such as sha384 and sha512). ........
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‎Doc/library/hashlib.rst‎

Lines changed: 9 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -52,6 +52,10 @@ spammish repetition'``::
5252
>>> m.update(b" the spammish repetition")
5353
>>> m.digest()
5454
b'\xbbd\x9c\x83\xdd\x1e\xa5\xc9\xd9\xde\xc9\xa1\x8d\xf0\xff\xe9'
55+
>>> m.digest_size
56+
16
57+
>>> m.block_size
58+
64
5559

5660
More condensed::
5761

@@ -76,7 +80,11 @@ returned by the constructors:
7680

7781
.. data:: digest_size
7882

79-
The size of the resulting digest in bytes.
83+
The size of the resulting hash in bytes.
84+
85+
.. data:: block_size
86+
87+
The internal block size of the hash algorithm in bytes.
8088

8189
A hash object has the following methods:
8290

‎Lib/hmac.py‎

Lines changed: 18 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -3,6 +3,8 @@
33
Implements the HMAC algorithm as described by RFC 2104.
44
"""
55

6+
import warnings as _warnings
7+
68
trans_5C = bytes((x ^ 0x5C) for x in range(256))
79
trans_36 = bytes((x ^ 0x36) for x in range(256))
810

@@ -16,7 +18,7 @@
1618
_secret_backdoor_key = []
1719

1820
class HMAC:
19-
"""RFC2104 HMAC class.
21+
"""RFC 2104 HMAC class. Also complies with RFC 4231.
2022
2123
This supports the API for Cryptographic Hash Functions (PEP 247).
2224
"""
@@ -52,7 +54,21 @@ def __init__(self, key, msg = None, digestmod = None):
5254
self.inner = self.digest_cons()
5355
self.digest_size = self.inner.digest_size
5456

55-
blocksize = self.blocksize
57+
if hasattr(self.inner, 'block_size'):
58+
blocksize = self.inner.block_size
59+
if blocksize < 16:
60+
# Very low blocksize, most likely a legacy value like
61+
# Lib/sha.py and Lib/md5.py have.
62+
_warnings.warn('block_size of %d seems too small; using our '
63+
'default of %d.' % (blocksize, self.blocksize),
64+
RuntimeWarning, 2)
65+
blocksize = self.blocksize
66+
else:
67+
_warnings.warn('No block_size attribute on given digest object; '
68+
'Assuming %d.' % (self.blocksize),
69+
RuntimeWarning, 2)
70+
blocksize = self.blocksize
71+
5672
if len(key) > blocksize:
5773
key = self.digest_cons(key).digest()
5874

‎Lib/test/test_hmac.py‎

Lines changed: 159 additions & 5 deletions
Original file line numberDiff line numberDiff line change
@@ -1,6 +1,7 @@
11
import hmac
2-
from hashlib import sha1
2+
import hashlib
33
import unittest
4+
import warnings
45
from test import test_support
56

67
class TestVectorsTestCase(unittest.TestCase):
@@ -43,7 +44,7 @@ def md5test(key, data, digest):
4344

4445
def test_sha_vectors(self):
4546
def shatest(key, data, digest):
46-
h = hmac.HMAC(key, data, digestmod=sha1)
47+
h = hmac.HMAC(key, data, digestmod=hashlib.sha1)
4748
self.assertEqual(h.hexdigest().upper(), digest.upper())
4849

4950
shatest(b"\x0b" * 20,
@@ -75,6 +76,161 @@ def shatest(key, data, digest):
7576
b"and Larger Than One Block-Size Data"),
7677
"e8e99d0f45237d786d6bbaa7965c7808bbff1a91")
7778

79+
def _rfc4231_test_cases(self, hashfunc):
80+
def hmactest(key, data, hexdigests):
81+
h = hmac.HMAC(key, data, digestmod=hashfunc)
82+
self.assertEqual(h.hexdigest().lower(), hexdigests[hashfunc])
83+
84+
# 4.2. Test Case 1
85+
hmactest(key = b'\x0b'*20,
86+
data = b'Hi There',
87+
hexdigests = {
88+
hashlib.sha224: '896fb1128abbdf196832107cd49df33f'
89+
'47b4b1169912ba4f53684b22',
90+
hashlib.sha256: 'b0344c61d8db38535ca8afceaf0bf12b'
91+
'881dc200c9833da726e9376c2e32cff7',
92+
hashlib.sha384: 'afd03944d84895626b0825f4ab46907f'
93+
'15f9dadbe4101ec682aa034c7cebc59c'
94+
'faea9ea9076ede7f4af152e8b2fa9cb6',
95+
hashlib.sha512: '87aa7cdea5ef619d4ff0b4241a1d6cb0'
96+
'2379f4e2ce4ec2787ad0b30545e17cde'
97+
'daa833b7d6b8a702038b274eaea3f4e4'
98+
'be9d914eeb61f1702e696c203a126854',
99+
})
100+
101+
# 4.3. Test Case 2
102+
hmactest(key = b'Jefe',
103+
data = b'what do ya want for nothing?',
104+
hexdigests = {
105+
hashlib.sha224: 'a30e01098bc6dbbf45690f3a7e9e6d0f'
106+
'8bbea2a39e6148008fd05e44',
107+
hashlib.sha256: '5bdcc146bf60754e6a042426089575c7'
108+
'5a003f089d2739839dec58b964ec3843',
109+
hashlib.sha384: 'af45d2e376484031617f78d2b58a6b1b'
110+
'9c7ef464f5a01b47e42ec3736322445e'
111+
'8e2240ca5e69e2c78b3239ecfab21649',
112+
hashlib.sha512: '164b7a7bfcf819e2e395fbe73b56e0a3'
113+
'87bd64222e831fd610270cd7ea250554'
114+
'9758bf75c05a994a6d034f65f8f0e6fd'
115+
'caeab1a34d4a6b4b636e070a38bce737',
116+
})
117+
118+
# 4.4. Test Case 3
119+
hmactest(key = b'\xaa'*20,
120+
data = b'\xdd'*50,
121+
hexdigests = {
122+
hashlib.sha224: '7fb3cb3588c6c1f6ffa9694d7d6ad264'
123+
'9365b0c1f65d69d1ec8333ea',
124+
hashlib.sha256: '773ea91e36800e46854db8ebd09181a7'
125+
'2959098b3ef8c122d9635514ced565fe',
126+
hashlib.sha384: '88062608d3e6ad8a0aa2ace014c8a86f'
127+
'0aa635d947ac9febe83ef4e55966144b'
128+
'2a5ab39dc13814b94e3ab6e101a34f27',
129+
hashlib.sha512: 'fa73b0089d56a284efb0f0756c890be9'
130+
'b1b5dbdd8ee81a3655f83e33b2279d39'
131+
'bf3e848279a722c806b485a47e67c807'
132+
'b946a337bee8942674278859e13292fb',
133+
})
134+
135+
# 4.5. Test Case 4
136+
hmactest(key = bytes(x for x in range(0x01, 0x19+1)),
137+
data = b'\xcd'*50,
138+
hexdigests = {
139+
hashlib.sha224: '6c11506874013cac6a2abc1bb382627c'
140+
'ec6a90d86efc012de7afec5a',
141+
hashlib.sha256: '82558a389a443c0ea4cc819899f2083a'
142+
'85f0faa3e578f8077a2e3ff46729665b',
143+
hashlib.sha384: '3e8a69b7783c25851933ab6290af6ca7'
144+
'7a9981480850009cc5577c6e1f573b4e'
145+
'6801dd23c4a7d679ccf8a386c674cffb',
146+
hashlib.sha512: 'b0ba465637458c6990e5a8c5f61d4af7'
147+
'e576d97ff94b872de76f8050361ee3db'
148+
'a91ca5c11aa25eb4d679275cc5788063'
149+
'a5f19741120c4f2de2adebeb10a298dd',
150+
})
151+
152+
# 4.7. Test Case 6
153+
hmactest(key = b'\xaa'*131,
154+
data = b'Test Using Larger Than Block-Siz'
155+
b'e Key - Hash Key First',
156+
hexdigests = {
157+
hashlib.sha224: '95e9a0db962095adaebe9b2d6f0dbce2'
158+
'd499f112f2d2b7273fa6870e',
159+
hashlib.sha256: '60e431591ee0b67f0d8a26aacbf5b77f'
160+
'8e0bc6213728c5140546040f0ee37f54',
161+
hashlib.sha384: '4ece084485813e9088d2c63a041bc5b4'
162+
'4f9ef1012a2b588f3cd11f05033ac4c6'
163+
'0c2ef6ab4030fe8296248df163f44952',
164+
hashlib.sha512: '80b24263c7c1a3ebb71493c1dd7be8b4'
165+
'9b46d1f41b4aeec1121b013783f8f352'
166+
'6b56d037e05f2598bd0fd2215d6a1e52'
167+
'95e64f73f63f0aec8b915a985d786598',
168+
})
169+
170+
# 4.8. Test Case 7
171+
hmactest(key = b'\xaa'*131,
172+
data = b'This is a test using a larger th'
173+
b'an block-size key and a larger t'
174+
b'han block-size data. The key nee'
175+
b'ds to be hashed before being use'
176+
b'd by the HMAC algorithm.',
177+
hexdigests = {
178+
hashlib.sha224: '3a854166ac5d9f023f54d517d0b39dbd'
179+
'946770db9c2b95c9f6f565d1',
180+
hashlib.sha256: '9b09ffa71b942fcb27635fbcd5b0e944'
181+
'bfdc63644f0713938a7f51535c3a35e2',
182+
hashlib.sha384: '6617178e941f020d351e2f254e8fd32c'
183+
'602420feb0b8fb9adccebb82461e99c5'
184+
'a678cc31e799176d3860e6110c46523e',
185+
hashlib.sha512: 'e37b6a775dc87dbaa4dfa9f96e5e3ffd'
186+
'debd71f8867289865df5a32d20cdc944'
187+
'b6022cac3c4982b10d5eeb55c3e4de15'
188+
'134676fb6de0446065c97440fa8c6a58',
189+
})
190+
191+
def test_sha224_rfc4231(self):
192+
self._rfc4231_test_cases(hashlib.sha224)
193+
194+
def test_sha256_rfc4231(self):
195+
self._rfc4231_test_cases(hashlib.sha256)
196+
197+
def test_sha384_rfc4231(self):
198+
self._rfc4231_test_cases(hashlib.sha384)
199+
200+
def test_sha512_rfc4231(self):
201+
self._rfc4231_test_cases(hashlib.sha512)
202+
203+
def test_legacy_block_size_warnings(self):
204+
class MockCrazyHash(object):
205+
"""Ain't no block_size attribute here."""
206+
def __init__(self, *args):
207+
self._x = hashlib.sha1(*args)
208+
self.digest_size = self._x.digest_size
209+
def update(self, v):
210+
self._x.update(v)
211+
def digest(self):
212+
return self._x.digest()
213+
214+
warnings.simplefilter('error', RuntimeWarning)
215+
try:
216+
try:
217+
hmac.HMAC(b'a', b'b', digestmod=MockCrazyHash)
218+
except RuntimeWarning:
219+
pass
220+
else:
221+
self.fail('Expected warning about missing block_size')
222+
223+
MockCrazyHash.block_size = 1
224+
try:
225+
hmac.HMAC(b'a', b'b', digestmod=MockCrazyHash)
226+
except RuntimeWarning:
227+
pass
228+
else:
229+
self.fail('Expected warning about small block_size')
230+
finally:
231+
warnings.resetwarnings()
232+
233+
78234

79235
class ConstructorTestCase(unittest.TestCase):
80236

@@ -95,9 +251,8 @@ def test_withtext(self):
95251

96252
def test_withmodule(self):
97253
# Constructor call with text and digest module.
98-
from hashlib import sha1
99254
try:
100-
h = hmac.HMAC(b"key", b"", sha1)
255+
h = hmac.HMAC(b"key", b"", hashlib.sha1)
101256
except:
102257
self.fail("Constructor call with hashlib.sha1 raised exception.")
103258

@@ -106,7 +261,6 @@ class SanityTestCase(unittest.TestCase):
106261
def test_default_is_md5(self):
107262
# Testing if HMAC defaults to MD5 algorithm.
108263
# NOTE: this whitebox test depends on the hmac class internals
109-
import hashlib
110264
h = hmac.HMAC(b"key")
111265
self.assertEqual(h.digest_cons, hashlib.md5)
112266

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