Viewing file:  crypto_shorthash.py (2.54 KB) -rw-r--r--
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# Copyright 2016 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.
import nacl.exceptions as exc
from nacl._sodium import ffi, lib
from nacl.exceptions import ensure
has_crypto_shorthash_siphashx24 = bool(
lib.PYNACL_HAS_CRYPTO_SHORTHASH_SIPHASHX24
)
BYTES: int = lib.crypto_shorthash_siphash24_bytes()
KEYBYTES: int = lib.crypto_shorthash_siphash24_keybytes()
XBYTES = 0
XKEYBYTES = 0
if has_crypto_shorthash_siphashx24:
XBYTES = lib.crypto_shorthash_siphashx24_bytes()
XKEYBYTES = lib.crypto_shorthash_siphashx24_keybytes()
def crypto_shorthash_siphash24(data: bytes, key: bytes) -> bytes:
"""Compute a fast, cryptographic quality, keyed hash of the input data
:param data:
:type data: bytes
:param key: len(key) must be equal to
:py:data:`.KEYBYTES` (16)
:type key: bytes
"""
if len(key) != KEYBYTES:
raise exc.ValueError(
"Key length must be exactly {} bytes".format(KEYBYTES)
)
digest = ffi.new("unsigned char[]", BYTES)
rc = lib.crypto_shorthash_siphash24(digest, data, len(data), key)
ensure(rc == 0, raising=exc.RuntimeError)
return ffi.buffer(digest, BYTES)[:]
def crypto_shorthash_siphashx24(data: bytes, key: bytes) -> bytes:
"""Compute a fast, cryptographic quality, keyed hash of the input data
:param data:
:type data: bytes
:param key: len(key) must be equal to
:py:data:`.XKEYBYTES` (16)
:type key: bytes
:raises nacl.exceptions.UnavailableError: If called when using a
minimal build of libsodium.
"""
ensure(
has_crypto_shorthash_siphashx24,
"Not available in minimal build",
raising=exc.UnavailableError,
)
if len(key) != XKEYBYTES:
raise exc.ValueError(
"Key length must be exactly {} bytes".format(XKEYBYTES)
)
digest = ffi.new("unsigned char[]", XBYTES)
rc = lib.crypto_shorthash_siphashx24(digest, data, len(data), key)
ensure(rc == 0, raising=exc.RuntimeError)
return ffi.buffer(digest, XBYTES)[:]
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