"""HMAC (Keyed-Hashing for Message Authentication) Python module.
Implements the HMAC algorithm as described by RFC 2104.
import warnings as _warnings
from _operator import _compare_digest as compare_digest
import hashlib as _hashlib
import _hashlib as _hashlibopenssl
trans_5C = bytes((x ^ 0x5C) for x in range(256))
trans_36 = bytes((x ^ 0x36) for x in range(256))
# The size of the digests returned by HMAC depends on the underlying
# hashing module used. Use digest_size from the instance of HMAC instead.
"""RFC 2104 HMAC class. Also complies with RFC 4231.
This supports the API for Cryptographic Hash Functions (PEP 247).
blocksize = 64 # 512-bit HMAC; can be changed in subclasses.
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. *OR*
A hashlib constructor returning a new hash object. *OR*
A hash name suitable for hashlib.new().
Implicit default to hashlib.md5 is deprecated and will be
Note: key and msg must be a bytes or bytearray objects.
if _hashlibopenssl.get_fips_mode():
'This class is not available in FIPS mode. '
if not isinstance(key, (bytes, bytearray)):
raise TypeError("key: expected bytes or bytearray, but got %r" % type(key).__name__)
_warnings.warn("HMAC() without an explicit digestmod argument "
"is deprecated.", PendingDeprecationWarning, 2)
self.digest_cons = digestmod
elif isinstance(digestmod, str):
self.digest_cons = lambda d=b'': _hashlib.new(digestmod, d)
self.digest_cons = lambda d=b'': digestmod.new(d)
self.outer = self.digest_cons()
self.inner = self.digest_cons()
self.digest_size = self.inner.digest_size
if hasattr(self.inner, 'block_size'):
blocksize = self.inner.block_size
_warnings.warn('block_size of %d seems too small; using our '
'default of %d.' % (blocksize, self.blocksize),
blocksize = self.blocksize
_warnings.warn('No block_size attribute on given digest object; '
'Assuming %d.' % (self.blocksize),
blocksize = self.blocksize
# self.blocksize is the default blocksize. self.block_size is
# effective block size as well as the public API attribute.
self.block_size = blocksize
key = self.digest_cons(key).digest()
key = key.ljust(blocksize, b'\0')
self.outer.update(key.translate(trans_5C))
self.inner.update(key.translate(trans_36))
return "hmac-" + self.inner.name
"""Update this hashing object with the string msg.
if _hashlibopenssl.get_fips_mode():
raise ValueError('hmac.HMAC is not available in FIPS mode')
"""Return a separate copy of this hashing object.
An update to this copy won't affect the original object.
# Call __new__ directly to avoid the expensive __init__.
other = self.__class__.__new__(self.__class__)
other.digest_cons = self.digest_cons
other.digest_size = self.digest_size
other.inner = self.inner.copy()
other.outer = self.outer.copy()
"""Return a hash object for the current state.
To be used only internally with digest() and hexdigest().
h.update(self.inner.digest())
"""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.
"""Like digest(), but returns a string of hexadecimal digits instead.
def _get_openssl_name(digestmod):
raise ValueError("'digestmod' argument is mandatory in FIPS mode")
if isinstance(digestmod, str):
elif callable(digestmod):
digestmod = digestmod(b'')
if not isinstance(digestmod, _hashlibopenssl.HASH):
'Only OpenSSL hashlib hashes are accepted in FIPS mode.')
return digestmod.name.lower().replace('_', '-')
class HMAC_openssl(_hmacopenssl.HMAC):
def __new__(cls, key, msg = None, digestmod = None):
if not isinstance(key, (bytes, bytearray)):
raise TypeError("key: expected bytes or bytearray, but got %r" % type(key).__name__)
name = _get_openssl_name(digestmod)
result = _hmacopenssl.HMAC.__new__(cls, key, digestmod=name)
if _hashlibopenssl.get_fips_mode():
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
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()
return HMAC(key, msg, digestmod)
It is recommended that you Edit text format, this type of Fix handles quite a lot in one request
