Python code coverage for Lib/hmac.py

#	count	content
1	n/a	"""HMAC (Keyed-Hashing for Message Authentication) Python module.
2	n/a
3	n/a	Implements the HMAC algorithm as described by RFC 2104.
4	n/a	"""
5	n/a
6	n/a	import warnings as _warnings
7	n/a	from _operator import _compare_digest as compare_digest
8	n/a	import hashlib as _hashlib
9	n/a
10	n/a	trans_5C = bytes((x ^ 0x5C) for x in range(256))
11	n/a	trans_36 = bytes((x ^ 0x36) for x in range(256))
12	n/a
13	n/a	# The size of the digests returned by HMAC depends on the underlying
14	n/a	# hashing module used. Use digest_size from the instance of HMAC instead.
15	n/a	digest_size = None
16	n/a
17	n/a
18	n/a
19	n/a	class HMAC:
20	n/a	"""RFC 2104 HMAC class. Also complies with RFC 4231.
21	n/a
22	n/a	This supports the API for Cryptographic Hash Functions (PEP 247).
23	n/a	"""
24	n/a	blocksize = 64 # 512-bit HMAC; can be changed in subclasses.
25	n/a
26	n/a	def __init__(self, key, msg = None, digestmod = None):
27	n/a	"""Create a new HMAC object.
28	n/a
29	n/a	key: key for the keyed hash object.
30	n/a	msg: Initial input for the hash, if provided.
31	n/a	digestmod: A module supporting PEP 247. OR
32	n/a	A hashlib constructor returning a new hash object. OR
33	n/a	A hash name suitable for hashlib.new().
34	n/a	Defaults to hashlib.md5.
35	n/a	Implicit default to hashlib.md5 is deprecated and will be
36	n/a	removed in Python 3.6.
37	n/a
38	n/a	Note: key and msg must be a bytes or bytearray objects.
39	n/a	"""
40	n/a
41	n/a	if not isinstance(key, (bytes, bytearray)):
42	n/a	raise TypeError("key: expected bytes or bytearray, but got %r" % type(key).__name__)
43	n/a
44	n/a	if digestmod is None:
45	n/a	_warnings.warn("HMAC() without an explicit digestmod argument "
46	n/a	"is deprecated.", PendingDeprecationWarning, 2)
47	n/a	digestmod = _hashlib.md5
48	n/a
49	n/a	if callable(digestmod):
50	n/a	self.digest_cons = digestmod
51	n/a	elif isinstance(digestmod, str):
52	n/a	self.digest_cons = lambda d=b'': _hashlib.new(digestmod, d)
53	n/a	else:
54	n/a	self.digest_cons = lambda d=b'': digestmod.new(d)
55	n/a
56	n/a	self.outer = self.digest_cons()
57	n/a	self.inner = self.digest_cons()
58	n/a	self.digest_size = self.inner.digest_size
59	n/a
60	n/a	if hasattr(self.inner, 'block_size'):
61	n/a	blocksize = self.inner.block_size
62	n/a	if blocksize < 16:
63	n/a	_warnings.warn('block_size of %d seems too small; using our '
64	n/a	'default of %d.' % (blocksize, self.blocksize),
65	n/a	RuntimeWarning, 2)
66	n/a	blocksize = self.blocksize
67	n/a	else:
68	n/a	_warnings.warn('No block_size attribute on given digest object; '
69	n/a	'Assuming %d.' % (self.blocksize),
70	n/a	RuntimeWarning, 2)
71	n/a	blocksize = self.blocksize
72	n/a
73	n/a	# self.blocksize is the default blocksize. self.block_size is
74	n/a	# effective block size as well as the public API attribute.
75	n/a	self.block_size = blocksize
76	n/a
77	n/a	if len(key) > blocksize:
78	n/a	key = self.digest_cons(key).digest()
79	n/a
80	n/a	key = key.ljust(blocksize, b'\0')
81	n/a	self.outer.update(key.translate(trans_5C))
82	n/a	self.inner.update(key.translate(trans_36))
83	n/a	if msg is not None:
84	n/a	self.update(msg)
85	n/a
86	n/a	@property
87	n/a	def name(self):
88	n/a	return "hmac-" + self.inner.name
89	n/a
90	n/a	def update(self, msg):
91	n/a	"""Update this hashing object with the string msg.
92	n/a	"""
93	n/a	self.inner.update(msg)
94	n/a
95	n/a	def copy(self):
96	n/a	"""Return a separate copy of this hashing object.
97	n/a
98	n/a	An update to this copy won't affect the original object.
99	n/a	"""
100	n/a	# Call __new__ directly to avoid the expensive __init__.
101	n/a	other = self.__class__.__new__(self.__class__)
102	n/a	other.digest_cons = self.digest_cons
103	n/a	other.digest_size = self.digest_size
104	n/a	other.inner = self.inner.copy()
105	n/a	other.outer = self.outer.copy()
106	n/a	return other
107	n/a
108	n/a	def _current(self):
109	n/a	"""Return a hash object for the current state.
110	n/a
111	n/a	To be used only internally with digest() and hexdigest().
112	n/a	"""
113	n/a	h = self.outer.copy()
114	n/a	h.update(self.inner.digest())
115	n/a	return h
116	n/a
117	n/a	def digest(self):
118	n/a	"""Return the hash value of this hashing object.
119	n/a
120	n/a	This returns a string containing 8-bit data. The object is
121	n/a	not altered in any way by this function; you can continue
122	n/a	updating the object after calling this function.
123	n/a	"""
124	n/a	h = self._current()
125	n/a	return h.digest()
126	n/a
127	n/a	def hexdigest(self):
128	n/a	"""Like digest(), but returns a string of hexadecimal digits instead.
129	n/a	"""
130	n/a	h = self._current()
131	n/a	return h.hexdigest()
132	n/a
133	n/a	def new(key, msg = None, digestmod = None):
134	n/a	"""Create a new hashing object and return it.
135	n/a
136	n/a	key: The starting key for the hash.
137	n/a	msg: if available, will immediately be hashed into the object's starting
138	n/a	state.
139	n/a
140	n/a	You can now feed arbitrary strings into the object using its update()
141	n/a	method, and can ask for the hash value at any time by calling its digest()
142	n/a	method.
143	n/a	"""
144	n/a	return HMAC(key, msg, digestmod)