def supported_by_hashlib_pbkdf2(self):
"""helper to detect if hash is supported by hashlib.pbkdf2_hmac()"""
if not _stdlib_pbkdf2_hmac:
return None
try:
_stdlib_pbkdf2_hmac(self.name, b"p", b"s", 1)
return True
except ValueError:
# "unsupported hash type"
return False
def supported_by_hashlib_pbkdf2(self):
"""helper to detect if hash is supported by hashlib.pbkdf2_hmac()"""
if not _stdlib_pbkdf2_hmac:
return None
try:
_stdlib_pbkdf2_hmac(self.name, b"p", b"s", 1)
return True
except ValueError:
# "unsupported hash type"
return False
def supported_by_hashlib_pbkdf2(self):
if not _stdlib_pbkdf2_hmac:
return
try:
_stdlib_pbkdf2_hmac(self.name, 'p', 's', 1)
return True
except ValueError:
return False
return
def pbkdf2_hmac(digest, secret, salt, rounds, keylen=None):
secret = to_bytes(secret, param='secret')
salt = to_bytes(salt, param='salt')
digest_info = lookup_hash(digest)
digest_size = digest_info.digest_size
if not isinstance(rounds, int_types):
raise exc.ExpectedTypeError(rounds, 'int', 'rounds')
if rounds < 1:
raise ValueError('rounds must be at least 1')
if keylen is None:
keylen = digest_size
else:
if not isinstance(keylen, int_types):
raise exc.ExpectedTypeError(keylen, 'int or None', 'keylen')
else:
if keylen < 1:
raise ValueError('keylen must be at least 1')
block_count = (keylen + digest_size - 1) // digest_size
if block_count > MAX_UINT32:
raise OverflowError('keylen too long for digest')
if digest_info.supported_by_fastpbkdf2:
return _fast_pbkdf2_hmac(digest_info.name, secret, salt,
rounds, keylen)
if digest_info.supported_by_hashlib_pbkdf2:
return _stdlib_pbkdf2_hmac(digest_info.name, secret, salt, rounds,
keylen)
keyed_hmac = compile_hmac(digest, secret)
calc_block = _get_pbkdf2_looper(digest_size)
return join_bytes(
calc_block(keyed_hmac, keyed_hmac(salt + _pack_uint32(i)), rounds)
for i in irange(1, block_count + 1))[:keylen]
def pbkdf2_hmac(digest, secret, salt, rounds, keylen=None):
"""pkcs#5 password-based key derivation v2.0 using HMAC + arbitrary digest.
:arg digest:
digest name or constructor.
:arg secret:
passphrase to use to generate key.
may be :class:`!bytes` or :class:`unicode` (encoded using UTF-8).
:arg salt:
salt string to use when generating key.
may be :class:`!bytes` or :class:`unicode` (encoded using UTF-8).
:param rounds:
number of rounds to use to generate key.
:arg keylen:
number of bytes to generate.
if omitted / ``None``, will use digest's native output size.
:returns:
raw bytes of generated key
.. versionchanged:: 1.7
This function will use the first available of the following backends:
* `fastpbk2 <https://pypi.python.org/pypi/fastpbkdf2>`_
* :func:`hashlib.pbkdf2_hmac` (only available in py2 >= 2.7.8, and py3 >= 3.4)
* builtin pure-python backend
See :data:`passlib.crypto.digest.PBKDF2_BACKENDS` to determine
which backend(s) are in use.
"""
# validate secret & salt
secret = to_bytes(secret, param="secret")
salt = to_bytes(salt, param="salt")
# resolve digest
digest_info = lookup_hash(digest)
digest_size = digest_info.digest_size
# validate rounds
if not isinstance(rounds, int_types):
raise exc.ExpectedTypeError(rounds, "int", "rounds")
if rounds < 1:
raise ValueError("rounds must be at least 1")
# validate keylen
if keylen is None:
keylen = digest_size
elif not isinstance(keylen, int_types):
raise exc.ExpectedTypeError(keylen, "int or None", "keylen")
elif keylen < 1:
# XXX: could allow keylen=0, but want to be compat w/ stdlib
raise ValueError("keylen must be at least 1")
# find smallest block count s.t. keylen <= block_count * digest_size;
# make sure block count won't overflow (per pbkdf2 spec)
# this corresponds to throwing error if keylen > digest_size * MAX_UINT32
# NOTE: stdlib will throw error at lower bound (keylen > MAX_SINT32)
# NOTE: have do this before other backends checked, since fastpbkdf2 raises wrong error
# (InvocationError, not OverflowError)
block_count = (keylen + digest_size - 1) // digest_size
if block_count > MAX_UINT32:
raise OverflowError("keylen too long for digest")
#
# check for various high-speed backends
#
# ~3x faster than pure-python backend
# NOTE: have to do this after above guards since fastpbkdf2 lacks bounds checks.
if digest_info.supported_by_fastpbkdf2:
return _fast_pbkdf2_hmac(digest_info.name, secret, salt, rounds,
keylen)
# ~1.4x faster than pure-python backend
# NOTE: have to do this after fastpbkdf2 since hashlib-ssl is slower,
# will support larger number of hashes.
if digest_info.supported_by_hashlib_pbkdf2:
return _stdlib_pbkdf2_hmac(digest_info.name, secret, salt, rounds,
keylen)
#
# otherwise use our own implementation
#
# generated keyed hmac
keyed_hmac = compile_hmac(digest, secret)
# get helper to calculate pbkdf2 inner loop efficiently
calc_block = _get_pbkdf2_looper(digest_size)
# assemble & return result
return join_bytes(
calc_block(keyed_hmac, keyed_hmac(salt + _pack_uint32(i)), rounds)
for i in irange(1, block_count + 1))[:keylen]
def pbkdf2_hmac(digest, secret, salt, rounds, keylen=None):
"""pkcs#5 password-based key derivation v2.0 using HMAC + arbitrary digest.
:arg digest:
digest name or constructor.
:arg secret:
passphrase to use to generate key.
may be :class:`!bytes` or :class:`unicode` (encoded using UTF-8).
:arg salt:
salt string to use when generating key.
may be :class:`!bytes` or :class:`unicode` (encoded using UTF-8).
:param rounds:
number of rounds to use to generate key.
:arg keylen:
number of bytes to generate.
if omitted / ``None``, will use digest's native output size.
:returns:
raw bytes of generated key
.. versionchanged:: 1.7
This function will use the first available of the following backends:
* `fastpbk2 <https://pypi.python.org/pypi/fastpbkdf2>`_
* :func:`hashlib.pbkdf2_hmac` (only available in py2 >= 2.7.8, and py3 >= 3.4)
* builtin pure-python backend
See :data:`passlib.crypto.digest.PBKDF2_BACKENDS` to determine
which backend(s) are in use.
"""
# validate secret & salt
secret = to_bytes(secret, param="secret")
salt = to_bytes(salt, param="salt")
# resolve digest
digest_info = lookup_hash(digest)
digest_size = digest_info.digest_size
# validate rounds
if not isinstance(rounds, int_types):
raise exc.ExpectedTypeError(rounds, "int", "rounds")
if rounds < 1:
raise ValueError("rounds must be at least 1")
# validate keylen
if keylen is None:
keylen = digest_size
elif not isinstance(keylen, int_types):
raise exc.ExpectedTypeError(keylen, "int or None", "keylen")
elif keylen < 1:
# XXX: could allow keylen=0, but want to be compat w/ stdlib
raise ValueError("keylen must be at least 1")
# find smallest block count s.t. keylen <= block_count * digest_size;
# make sure block count won't overflow (per pbkdf2 spec)
# this corresponds to throwing error if keylen > digest_size * MAX_UINT32
# NOTE: stdlib will throw error at lower bound (keylen > MAX_SINT32)
# NOTE: have do this before other backends checked, since fastpbkdf2 raises wrong error
# (InvocationError, not OverflowError)
block_count = (keylen + digest_size - 1) // digest_size
if block_count > MAX_UINT32:
raise OverflowError("keylen too long for digest")
#
# check for various high-speed backends
#
# ~3x faster than pure-python backend
# NOTE: have to do this after above guards since fastpbkdf2 lacks bounds checks.
if digest_info.supported_by_fastpbkdf2:
return _fast_pbkdf2_hmac(digest_info.name, secret, salt, rounds, keylen)
# ~1.4x faster than pure-python backend
# NOTE: have to do this after fastpbkdf2 since hashlib-ssl is slower,
# will support larger number of hashes.
if digest_info.supported_by_hashlib_pbkdf2:
return _stdlib_pbkdf2_hmac(digest_info.name, secret, salt, rounds, keylen)
#
# otherwise use our own implementation
#
# generated keyed hmac
keyed_hmac = compile_hmac(digest, secret)
# get helper to calculate pbkdf2 inner loop efficiently
calc_block = _get_pbkdf2_looper(digest_size)
# assemble & return result
return join_bytes(
calc_block(keyed_hmac, keyed_hmac(salt + _pack_uint32(i)), rounds)
for i in irange(1, block_count + 1)
)[:keylen]