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# Copyright 2013-2019 Donald Stufft and individual contributors
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
from typing import NoReturn, TypeVar
from nacl import exceptions as exc
from nacl._sodium import ffi, lib
from nacl.exceptions import ensure
crypto_generichash_BYTES: int = lib.crypto_generichash_blake2b_bytes()
crypto_generichash_BYTES_MIN: int = lib.crypto_generichash_blake2b_bytes_min()
crypto_generichash_BYTES_MAX: int = lib.crypto_generichash_blake2b_bytes_max()
crypto_generichash_KEYBYTES: int = lib.crypto_generichash_blake2b_keybytes()
crypto_generichash_KEYBYTES_MIN: int = (
lib.crypto_generichash_blake2b_keybytes_min()
)
crypto_generichash_KEYBYTES_MAX: int = (
lib.crypto_generichash_blake2b_keybytes_max()
)
crypto_generichash_SALTBYTES: int = lib.crypto_generichash_blake2b_saltbytes()
crypto_generichash_PERSONALBYTES: int = (
lib.crypto_generichash_blake2b_personalbytes()
)
crypto_generichash_STATEBYTES: int = lib.crypto_generichash_statebytes()
_OVERLONG = "{0} length greater than {1} bytes"
_TOOBIG = "{0} greater than {1}"
def _checkparams(
digest_size: int, key: bytes, salt: bytes, person: bytes
) -> None:
"""Check hash parameters"""
ensure(
isinstance(key, bytes),
"Key must be a bytes sequence",
raising=exc.TypeError,
)
ensure(
isinstance(salt, bytes),
"Salt must be a bytes sequence",
raising=exc.TypeError,
)
ensure(
isinstance(person, bytes),
"Person must be a bytes sequence",
raising=exc.TypeError,
)
ensure(
isinstance(digest_size, int),
"Digest size must be an integer number",
raising=exc.TypeError,
)
ensure(
digest_size <= crypto_generichash_BYTES_MAX,
_TOOBIG.format("Digest_size", crypto_generichash_BYTES_MAX),
raising=exc.ValueError,
)
ensure(
len(key) <= crypto_generichash_KEYBYTES_MAX,
_OVERLONG.format("Key", crypto_generichash_KEYBYTES_MAX),
raising=exc.ValueError,
)
ensure(
len(salt) <= crypto_generichash_SALTBYTES,
_OVERLONG.format("Salt", crypto_generichash_SALTBYTES),
raising=exc.ValueError,
)
ensure(
len(person) <= crypto_generichash_PERSONALBYTES,
_OVERLONG.format("Person", crypto_generichash_PERSONALBYTES),
raising=exc.ValueError,
)
def generichash_blake2b_salt_personal(
data: bytes,
digest_size: int = crypto_generichash_BYTES,
key: bytes = b"",
salt: bytes = b"",
person: bytes = b"",
) -> bytes:
"""One shot hash interface
:param data: the input data to the hash function
:type data: bytes
:param digest_size: must be at most
:py:data:`.crypto_generichash_BYTES_MAX`;
the default digest size is
:py:data:`.crypto_generichash_BYTES`
:type digest_size: int
:param key: must be at most
:py:data:`.crypto_generichash_KEYBYTES_MAX` long
:type key: bytes
:param salt: must be at most
:py:data:`.crypto_generichash_SALTBYTES` long;
will be zero-padded if needed
:type salt: bytes
:param person: must be at most
:py:data:`.crypto_generichash_PERSONALBYTES` long:
will be zero-padded if needed
:type person: bytes
:return: digest_size long digest
:rtype: bytes
"""
_checkparams(digest_size, key, salt, person)
ensure(
isinstance(data, bytes),
"Input data must be a bytes sequence",
raising=exc.TypeError,
)
digest = ffi.new("unsigned char[]", digest_size)
# both _salt and _personal must be zero-padded to the correct length
_salt = ffi.new("unsigned char []", crypto_generichash_SALTBYTES)
_person = ffi.new("unsigned char []", crypto_generichash_PERSONALBYTES)
ffi.memmove(_salt, salt, len(salt))
ffi.memmove(_person, person, len(person))
rc = lib.crypto_generichash_blake2b_salt_personal(
digest, digest_size, data, len(data), key, len(key), _salt, _person
)
ensure(rc == 0, "Unexpected failure", raising=exc.RuntimeError)
return ffi.buffer(digest, digest_size)[:]
_Blake2State = TypeVar("_Blake2State", bound="Blake2State")
class Blake2State:
"""
Python-level wrapper for the crypto_generichash_blake2b state buffer
"""
__slots__ = ["_statebuf", "digest_size"]
def __init__(self, digest_size: int):
self._statebuf = ffi.new(
"unsigned char[]", crypto_generichash_STATEBYTES
)
self.digest_size = digest_size
def __reduce__(self) -> NoReturn:
"""
Raise the same exception as hashlib's blake implementation
on copy.copy()
"""
raise TypeError(
"can't pickle {} objects".format(self.__class__.__name__)
)
def copy(self: _Blake2State) -> _Blake2State:
_st = self.__class__(self.digest_size)
ffi.memmove(
_st._statebuf, self._statebuf, crypto_generichash_STATEBYTES
)
return _st
def generichash_blake2b_init(
key: bytes = b"",
salt: bytes = b"",
person: bytes = b"",
digest_size: int = crypto_generichash_BYTES,
) -> Blake2State:
"""
Create a new initialized blake2b hash state
:param key: must be at most
:py:data:`.crypto_generichash_KEYBYTES_MAX` long
:type key: bytes
:param salt: must be at most
:py:data:`.crypto_generichash_SALTBYTES` long;
will be zero-padded if needed
:type salt: bytes
:param person: must be at most
:py:data:`.crypto_generichash_PERSONALBYTES` long:
will be zero-padded if needed
:type person: bytes
:param digest_size: must be at most
:py:data:`.crypto_generichash_BYTES_MAX`;
the default digest size is
:py:data:`.crypto_generichash_BYTES`
:type digest_size: int
:return: a initialized :py:class:`.Blake2State`
:rtype: object
"""
_checkparams(digest_size, key, salt, person)
state = Blake2State(digest_size)
# both _salt and _personal must be zero-padded to the correct length
_salt = ffi.new("unsigned char []", crypto_generichash_SALTBYTES)
_person = ffi.new("unsigned char []", crypto_generichash_PERSONALBYTES)
ffi.memmove(_salt, salt, len(salt))
ffi.memmove(_person, person, len(person))
rc = lib.crypto_generichash_blake2b_init_salt_personal(
state._statebuf, key, len(key), digest_size, _salt, _person
)
ensure(rc == 0, "Unexpected failure", raising=exc.RuntimeError)
return state
def generichash_blake2b_update(state: Blake2State, data: bytes) -> None:
"""Update the blake2b hash state
:param state: a initialized Blake2bState object as returned from
:py:func:`.crypto_generichash_blake2b_init`
:type state: :py:class:`.Blake2State`
:param data:
:type data: bytes
"""
ensure(
isinstance(state, Blake2State),
"State must be a Blake2State object",
raising=exc.TypeError,
)
ensure(
isinstance(data, bytes),
"Input data must be a bytes sequence",
raising=exc.TypeError,
)
rc = lib.crypto_generichash_blake2b_update(
state._statebuf, data, len(data)
)
ensure(rc == 0, "Unexpected failure", raising=exc.RuntimeError)
def generichash_blake2b_final(state: Blake2State) -> bytes:
"""Finalize the blake2b hash state and return the digest.
:param state: a initialized Blake2bState object as returned from
:py:func:`.crypto_generichash_blake2b_init`
:type state: :py:class:`.Blake2State`
:return: the blake2 digest of the passed-in data stream
:rtype: bytes
"""
ensure(
isinstance(state, Blake2State),
"State must be a Blake2State object",
raising=exc.TypeError,
)
_digest = ffi.new("unsigned char[]", crypto_generichash_BYTES_MAX)
rc = lib.crypto_generichash_blake2b_final(
state._statebuf, _digest, state.digest_size
)
ensure(rc == 0, "Unexpected failure", raising=exc.RuntimeError)
return ffi.buffer(_digest, state.digest_size)[:]
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