212 lines
6.8 KiB
Python
212 lines
6.8 KiB
Python
# Copyright 2013 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 cast
|
|
|
|
import nacl.bindings
|
|
import nacl.encoding
|
|
from nacl import exceptions as exc
|
|
from nacl.exceptions import ensure
|
|
|
|
_strbytes_plus_one = nacl.bindings.crypto_pwhash_scryptsalsa208sha256_STRBYTES
|
|
|
|
AVAILABLE = nacl.bindings.has_crypto_pwhash_scryptsalsa208sha256
|
|
|
|
STRPREFIX = nacl.bindings.crypto_pwhash_scryptsalsa208sha256_STRPREFIX
|
|
|
|
SALTBYTES = nacl.bindings.crypto_pwhash_scryptsalsa208sha256_SALTBYTES
|
|
|
|
PASSWD_MIN = nacl.bindings.crypto_pwhash_scryptsalsa208sha256_PASSWD_MIN
|
|
PASSWD_MAX = nacl.bindings.crypto_pwhash_scryptsalsa208sha256_PASSWD_MAX
|
|
|
|
PWHASH_SIZE = _strbytes_plus_one - 1
|
|
|
|
BYTES_MIN = nacl.bindings.crypto_pwhash_scryptsalsa208sha256_BYTES_MIN
|
|
BYTES_MAX = nacl.bindings.crypto_pwhash_scryptsalsa208sha256_BYTES_MAX
|
|
|
|
MEMLIMIT_MIN = nacl.bindings.crypto_pwhash_scryptsalsa208sha256_MEMLIMIT_MIN
|
|
MEMLIMIT_MAX = nacl.bindings.crypto_pwhash_scryptsalsa208sha256_MEMLIMIT_MAX
|
|
OPSLIMIT_MIN = nacl.bindings.crypto_pwhash_scryptsalsa208sha256_OPSLIMIT_MIN
|
|
OPSLIMIT_MAX = nacl.bindings.crypto_pwhash_scryptsalsa208sha256_OPSLIMIT_MAX
|
|
|
|
OPSLIMIT_INTERACTIVE = (
|
|
nacl.bindings.crypto_pwhash_scryptsalsa208sha256_OPSLIMIT_INTERACTIVE
|
|
)
|
|
MEMLIMIT_INTERACTIVE = (
|
|
nacl.bindings.crypto_pwhash_scryptsalsa208sha256_MEMLIMIT_INTERACTIVE
|
|
)
|
|
OPSLIMIT_SENSITIVE = (
|
|
nacl.bindings.crypto_pwhash_scryptsalsa208sha256_OPSLIMIT_SENSITIVE
|
|
)
|
|
MEMLIMIT_SENSITIVE = (
|
|
nacl.bindings.crypto_pwhash_scryptsalsa208sha256_MEMLIMIT_SENSITIVE
|
|
)
|
|
|
|
OPSLIMIT_MODERATE = 8 * OPSLIMIT_INTERACTIVE
|
|
MEMLIMIT_MODERATE = 8 * MEMLIMIT_INTERACTIVE
|
|
|
|
|
|
def kdf(
|
|
size: int,
|
|
password: bytes,
|
|
salt: bytes,
|
|
opslimit: int = OPSLIMIT_SENSITIVE,
|
|
memlimit: int = MEMLIMIT_SENSITIVE,
|
|
encoder: nacl.encoding.Encoder = nacl.encoding.RawEncoder,
|
|
) -> bytes:
|
|
"""
|
|
Derive a ``size`` bytes long key from a caller-supplied
|
|
``password`` and ``salt`` pair using the scryptsalsa208sha256
|
|
memory-hard construct.
|
|
|
|
|
|
the enclosing module provides the constants
|
|
|
|
- :py:const:`.OPSLIMIT_INTERACTIVE`
|
|
- :py:const:`.MEMLIMIT_INTERACTIVE`
|
|
- :py:const:`.OPSLIMIT_SENSITIVE`
|
|
- :py:const:`.MEMLIMIT_SENSITIVE`
|
|
- :py:const:`.OPSLIMIT_MODERATE`
|
|
- :py:const:`.MEMLIMIT_MODERATE`
|
|
|
|
as a guidance for correct settings respectively for the
|
|
interactive login and the long term key protecting sensitive data
|
|
use cases.
|
|
|
|
:param size: derived key size, must be between
|
|
:py:const:`.BYTES_MIN` and
|
|
:py:const:`.BYTES_MAX`
|
|
:type size: int
|
|
:param password: password used to seed the key derivation procedure;
|
|
it length must be between
|
|
:py:const:`.PASSWD_MIN` and
|
|
:py:const:`.PASSWD_MAX`
|
|
:type password: bytes
|
|
:param salt: **RANDOM** salt used in the key derivation procedure;
|
|
its length must be exactly :py:const:`.SALTBYTES`
|
|
:type salt: bytes
|
|
:param opslimit: the time component (operation count)
|
|
of the key derivation procedure's computational cost;
|
|
it must be between
|
|
:py:const:`.OPSLIMIT_MIN` and
|
|
:py:const:`.OPSLIMIT_MAX`
|
|
:type opslimit: int
|
|
:param memlimit: the memory occupation component
|
|
of the key derivation procedure's computational cost;
|
|
it must be between
|
|
:py:const:`.MEMLIMIT_MIN` and
|
|
:py:const:`.MEMLIMIT_MAX`
|
|
:type memlimit: int
|
|
:rtype: bytes
|
|
:raises nacl.exceptions.UnavailableError: If called when using a
|
|
minimal build of libsodium.
|
|
|
|
.. versionadded:: 1.2
|
|
"""
|
|
ensure(
|
|
AVAILABLE,
|
|
"Not available in minimal build",
|
|
raising=exc.UnavailableError,
|
|
)
|
|
|
|
ensure(
|
|
len(salt) == SALTBYTES,
|
|
"The salt must be exactly %s, not %s bytes long"
|
|
% (SALTBYTES, len(salt)),
|
|
raising=exc.ValueError,
|
|
)
|
|
|
|
n_log2, r, p = nacl.bindings.nacl_bindings_pick_scrypt_params(
|
|
opslimit, memlimit
|
|
)
|
|
maxmem = memlimit + (2 ** 16)
|
|
|
|
return encoder.encode(
|
|
nacl.bindings.crypto_pwhash_scryptsalsa208sha256_ll(
|
|
password,
|
|
salt,
|
|
# Cast safety: n_log2 is a positive integer, and so 2 ** n_log2 is also
|
|
# a positive integer. Mypy+typeshed can't deduce this, because there's no
|
|
# way to for them to know that n_log2: int is positive.
|
|
cast(int, 2 ** n_log2),
|
|
r,
|
|
p,
|
|
maxmem=maxmem,
|
|
dklen=size,
|
|
)
|
|
)
|
|
|
|
|
|
def str(
|
|
password: bytes,
|
|
opslimit: int = OPSLIMIT_INTERACTIVE,
|
|
memlimit: int = MEMLIMIT_INTERACTIVE,
|
|
) -> bytes:
|
|
"""
|
|
Hashes a password with a random salt, using the memory-hard
|
|
scryptsalsa208sha256 construct and returning an ascii string
|
|
that has all the needed info to check against a future password
|
|
|
|
The default settings for opslimit and memlimit are those deemed
|
|
correct for the interactive user login case.
|
|
|
|
:param bytes password:
|
|
:param int opslimit:
|
|
:param int memlimit:
|
|
:rtype: bytes
|
|
:raises nacl.exceptions.UnavailableError: If called when using a
|
|
minimal build of libsodium.
|
|
|
|
.. versionadded:: 1.2
|
|
"""
|
|
ensure(
|
|
AVAILABLE,
|
|
"Not available in minimal build",
|
|
raising=exc.UnavailableError,
|
|
)
|
|
|
|
return nacl.bindings.crypto_pwhash_scryptsalsa208sha256_str(
|
|
password, opslimit, memlimit
|
|
)
|
|
|
|
|
|
def verify(password_hash: bytes, password: bytes) -> bool:
|
|
"""
|
|
Takes the output of scryptsalsa208sha256 and compares it against
|
|
a user provided password to see if they are the same
|
|
|
|
:param password_hash: bytes
|
|
:param password: bytes
|
|
:rtype: boolean
|
|
:raises nacl.exceptions.UnavailableError: If called when using a
|
|
minimal build of libsodium.
|
|
|
|
.. versionadded:: 1.2
|
|
"""
|
|
ensure(
|
|
AVAILABLE,
|
|
"Not available in minimal build",
|
|
raising=exc.UnavailableError,
|
|
)
|
|
|
|
ensure(
|
|
len(password_hash) == PWHASH_SIZE,
|
|
"The password hash must be exactly %s bytes long"
|
|
% nacl.bindings.crypto_pwhash_scryptsalsa208sha256_STRBYTES,
|
|
raising=exc.ValueError,
|
|
)
|
|
|
|
return nacl.bindings.crypto_pwhash_scryptsalsa208sha256_str_verify(
|
|
password_hash, password
|
|
)
|