mirror of
https://github.com/markqvist/Reticulum.git
synced 2024-08-21 22:50:28 +00:00
183 lines
6.7 KiB
Python
183 lines
6.7 KiB
Python
# This HMAC implementation comes directly from the HMAC implementation
|
|
# included in Python 3.10.4, and is almost completely identical. It has
|
|
# been modified to be a pure Python implementation, that is not dependent
|
|
# on the system having OpenSSL binaries installed.
|
|
|
|
import warnings as _warnings
|
|
import hashlib as _hashlib
|
|
|
|
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.
|
|
digest_size = None
|
|
|
|
|
|
class HMAC:
|
|
"""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.
|
|
|
|
__slots__ = (
|
|
"_hmac", "_inner", "_outer", "block_size", "digest_size"
|
|
)
|
|
|
|
def __init__(self, key, msg=None, digestmod=_hashlib.sha256):
|
|
"""Create a new HMAC object.
|
|
key: bytes or buffer, key for the keyed hash object.
|
|
msg: bytes or buffer, Initial input for the hash or None.
|
|
digestmod: A hash name suitable for hashlib.new(). *OR*
|
|
A hashlib constructor returning a new hash object. *OR*
|
|
A module supporting PEP 247.
|
|
Required as of 3.8, despite its position after the optional
|
|
msg argument. Passing it as a keyword argument is
|
|
recommended, though not required for legacy API reasons.
|
|
"""
|
|
|
|
if not isinstance(key, (bytes, bytearray)):
|
|
raise TypeError("key: expected bytes or bytearray, but got %r" % type(key).__name__)
|
|
|
|
if not digestmod:
|
|
raise TypeError("Missing required parameter 'digestmod'.")
|
|
|
|
self._hmac_init(key, msg, digestmod)
|
|
|
|
def _hmac_init(self, key, msg, digestmod):
|
|
if callable(digestmod):
|
|
digest_cons = digestmod
|
|
elif isinstance(digestmod, str):
|
|
digest_cons = lambda d=b'': _hashlib.new(digestmod, d)
|
|
else:
|
|
digest_cons = lambda d=b'': digestmod.new(d)
|
|
|
|
self._hmac = None
|
|
self._outer = digest_cons()
|
|
self._inner = digest_cons()
|
|
self.digest_size = self._inner.digest_size
|
|
|
|
if hasattr(self._inner, 'block_size'):
|
|
blocksize = self._inner.block_size
|
|
if blocksize < 16:
|
|
_warnings.warn('block_size of %d seems too small; using our '
|
|
'default of %d.' % (blocksize, self.blocksize),
|
|
RuntimeWarning, 2)
|
|
blocksize = self.blocksize
|
|
else:
|
|
_warnings.warn('No block_size attribute on given digest object; '
|
|
'Assuming %d.' % (self.blocksize),
|
|
RuntimeWarning, 2)
|
|
blocksize = self.blocksize
|
|
|
|
if len(key) > blocksize:
|
|
key = digest_cons(key).digest()
|
|
|
|
# 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 = key.ljust(blocksize, b'\0')
|
|
self._outer.update(key.translate(trans_5C))
|
|
self._inner.update(key.translate(trans_36))
|
|
if msg is not None:
|
|
self.update(msg)
|
|
|
|
@property
|
|
def name(self):
|
|
if self._hmac:
|
|
return self._hmac.name
|
|
else:
|
|
return f"hmac-{self._inner.name}"
|
|
|
|
def update(self, msg):
|
|
"""Feed data from msg into this hashing object."""
|
|
inst = self._hmac or self._inner
|
|
inst.update(msg)
|
|
|
|
def copy(self):
|
|
"""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_size = self.digest_size
|
|
if self._hmac:
|
|
other._hmac = self._hmac.copy()
|
|
other._inner = other._outer = None
|
|
else:
|
|
other._hmac = None
|
|
other._inner = self._inner.copy()
|
|
other._outer = self._outer.copy()
|
|
return other
|
|
|
|
def _current(self):
|
|
"""Return a hash object for the current state.
|
|
To be used only internally with digest() and hexdigest().
|
|
"""
|
|
if self._hmac:
|
|
return self._hmac
|
|
else:
|
|
h = self._outer.copy()
|
|
h.update(self._inner.digest())
|
|
return h
|
|
|
|
def digest(self):
|
|
"""Return the hash value of this hashing object.
|
|
This returns the hmac value as bytes. The object is
|
|
not altered in any way by this function; you can continue
|
|
updating the object after calling this function.
|
|
"""
|
|
h = self._current()
|
|
return h.digest()
|
|
|
|
def hexdigest(self):
|
|
"""Like digest(), but returns a string of hexadecimal digits instead.
|
|
"""
|
|
h = self._current()
|
|
return h.hexdigest()
|
|
|
|
def new(key, msg=None, digestmod=_hashlib.sha256):
|
|
"""Create a new hashing object and return it.
|
|
key: bytes or buffer, The starting key for the hash.
|
|
msg: bytes or buffer, Initial input for the hash, or None.
|
|
digestmod: A hash name suitable for hashlib.new(). *OR*
|
|
A hashlib constructor returning a new hash object. *OR*
|
|
A module supporting PEP 247.
|
|
Required as of 3.8, despite its position after the optional
|
|
msg argument. Passing it as a keyword argument is
|
|
recommended, though not required for legacy API reasons.
|
|
You can now feed arbitrary bytes into the object using its update()
|
|
method, and can ask for the hash value at any time by calling its digest()
|
|
or hexdigest() methods.
|
|
"""
|
|
return HMAC(key, msg, digestmod)
|
|
|
|
|
|
def digest(key, msg, digest):
|
|
"""Fast inline implementation of HMAC.
|
|
key: bytes or buffer, The key for the keyed hash object.
|
|
msg: bytes or buffer, Input message.
|
|
digest: A hash name suitable for hashlib.new() for best performance. *OR*
|
|
A hashlib constructor returning a new hash object. *OR*
|
|
A module supporting PEP 247.
|
|
"""
|
|
if callable(digest):
|
|
digest_cons = digest
|
|
elif isinstance(digest, str):
|
|
digest_cons = lambda d=b'': _hashlib.new(digest, d)
|
|
else:
|
|
digest_cons = lambda d=b'': digest.new(d)
|
|
|
|
inner = digest_cons()
|
|
outer = digest_cons()
|
|
blocksize = getattr(inner, 'block_size', 64)
|
|
if len(key) > blocksize:
|
|
key = digest_cons(key).digest()
|
|
|
|
key = key + b'\x00' * (blocksize - len(key))
|
|
inner.update(key.translate(trans_36))
|
|
outer.update(key.translate(trans_5C))
|
|
inner.update(msg)
|
|
outer.update(inner.digest())
|
|
return outer.digest() |