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#!/usr/bin/env python
# Copyright (c) 2014, Jan Varho
#
# Permission to use, copy, modify, and/or distribute this software for any
# purpose with or without fee is hereby granted, provided that the above
# copyright notice and this permission notice appear in all copies.
#
# THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
# OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
"""Scrypt implementation that calls into system libsodium"""
import base64
import ctypes, ctypes.util
from ctypes import c_char_p, c_size_t, c_uint64, c_uint32, c_void_p
import hashlib, hmac
import numbers
import platform
import struct
import sys
from . import mcf as mcf_mod
from .common import *
if platform.python_implementation() == 'PyPy':
from . import pypyscrypt_inline as scr_mod
else:
from . import pylibsodium_salsa as scr_mod
def _get_libsodium():
'''
Locate the nacl c libs to use
'''
__SONAMES = (13, 10, 5, 4)
# Import libsodium from system
sys_sodium = ctypes.util.find_library('sodium')
if sys_sodium is None:
sys_sodium = ctypes.util.find_library('libsodium')
if sys_sodium:
return ctypes.CDLL(sys_sodium)
# Import from local path
if sys.platform.startswith('win'):
try:
return ctypes.cdll.LoadLibrary('libsodium')
except OSError:
pass
for soname_ver in __SONAMES:
try:
return ctypes.cdll.LoadLibrary(
'libsodium-{0}'.format(soname_ver)
)
except OSError:
pass
elif sys.platform.startswith('darwin'):
try:
return ctypes.cdll.LoadLibrary('libsodium.dylib')
except OSError:
pass
else:
try:
return ctypes.cdll.LoadLibrary('libsodium.so')
except OSError:
pass
for soname_ver in __SONAMES:
try:
return ctypes.cdll.LoadLibrary(
'libsodium.so.{0}'.format(soname_ver)
)
except OSError:
pass
_lib = _get_libsodium()
if _lib is None:
raise ImportError('Unable to load libsodium')
try:
_scrypt_ll = _lib.crypto_pwhash_scryptsalsa208sha256_ll
_scrypt_ll.argtypes = [
c_void_p, # passwd
c_size_t, # passwdlen
c_void_p, # salt
c_size_t, # saltlen
c_uint64, # N
c_uint32, # r
c_uint32, # p
c_void_p, # buf
c_size_t, # buflen
]
except AttributeError:
_scrypt_ll = None
try:
_scrypt = _lib.crypto_pwhash_scryptsalsa208sha256
_scrypt_str = _lib.crypto_pwhash_scryptsalsa208sha256_str
_scrypt_str_chk = _lib.crypto_pwhash_scryptsalsa208sha256_str_verify
_scrypt_str_bytes = _lib.crypto_pwhash_scryptsalsa208sha256_strbytes()
_scrypt_salt = _lib.crypto_pwhash_scryptsalsa208sha256_saltbytes()
if _scrypt_str_bytes != 102 and not _scrypt_ll:
raise ImportError('Incompatible libsodium: ' + _lib_soname)
except AttributeError:
try:
_scrypt = _lib.crypto_pwhash_scryptxsalsa208sha256
_scrypt_str = _lib.crypto_pwhash_scryptxsalsa208sha256_str
_scrypt_str_chk = _lib.crypto_pwhash_scryptxsalsa208sha256_str_verify
_scrypt_str_bytes = _lib.crypto_pwhash_scryptxsalsa208sha256_strbytes()
_scrypt_salt = _lib.crypto_pwhash_scryptxsalsa208sha256_saltbytes
_scrypt_salt = _scrypt_salt()
if _scrypt_str_bytes != 102 and not _scrypt_ll:
raise ImportError('Incompatible libsodium: ' + _lib_soname)
except AttributeError:
if not _scrypt_ll:
raise ImportError('Incompatible libsodium: ' + _lib_soname)
_scrypt.argtypes = [
c_void_p, # out
c_uint64, # outlen
c_void_p, # passwd
c_uint64, # passwdlen
c_void_p, # salt
c_uint64, # opslimit
c_size_t, # memlimit
]
_scrypt_str.argtypes = [
c_void_p, # out (102 bytes)
c_void_p, # passwd
c_uint64, # passwdlen
c_uint64, # opslimit
c_size_t, # memlimit
]
_scrypt_str_chk.argtypes = [
c_char_p, # str (102 bytes)
c_void_p, # passwd
c_uint64, # passwdlen
]
def scrypt(password, salt, N=SCRYPT_N, r=SCRYPT_r, p=SCRYPT_p, olen=64):
"""Returns a key derived using the scrypt key-derivarion function
N must be a power of two larger than 1 but no larger than 2 ** 63 (insane)
r and p must be positive numbers such that r * p < 2 ** 30
The default values are:
N -- 2**14 (~16k)
r -- 8
p -- 1
Memory usage is proportional to N*r. Defaults require about 16 MiB.
Time taken is proportional to N*p. Defaults take <100ms of a recent x86.
The last one differs from libscrypt defaults, but matches the 'interactive'
work factor from the original paper. For long term storage where runtime of
key derivation is not a problem, you could use 16 as in libscrypt or better
yet increase N if memory is plentiful.
"""
check_args(password, salt, N, r, p, olen)
if _scrypt_ll:
out = ctypes.create_string_buffer(olen)
if _scrypt_ll(password, len(password), salt, len(salt),
N, r, p, out, olen):
raise ValueError
return out.raw
if len(salt) != _scrypt_salt or r != 8 or (p & (p - 1)) or (N*p <= 512):
return scr_mod.scrypt(password, salt, N, r, p, olen)
s = next(i for i in range(1, 64) if 2**i == N)
t = next(i for i in range(0, 30) if 2**i == p)
m = 2**(10 + s)
o = 2**(5 + t + s)
if s > 53 or t + s > 58:
raise ValueError
out = ctypes.create_string_buffer(olen)
if _scrypt(out, olen, password, len(password), salt, o, m) != 0:
raise ValueError
return out.raw
def scrypt_mcf(password, salt=None, N=SCRYPT_N, r=SCRYPT_r, p=SCRYPT_p,
prefix=SCRYPT_MCF_PREFIX_DEFAULT):
"""Derives a Modular Crypt Format hash using the scrypt KDF
Parameter space is smaller than for scrypt():
N must be a power of two larger than 1 but no larger than 2 ** 31
r and p must be positive numbers between 1 and 255
Salt must be a byte string 1-16 bytes long.
If no salt is given, a random salt of 128+ bits is used. (Recommended.)
"""
if N < 2 or (N & (N - 1)):
raise ValueError('scrypt N must be a power of 2 greater than 1')
if p > 255 or p < 1:
raise ValueError('scrypt_mcf p out of range [1,255]')
if N > 2**31:
raise ValueError('scrypt_mcf N out of range [2,2**31]')
if (salt is not None or r != 8 or (p & (p - 1)) or (N*p <= 512) or
prefix not in (SCRYPT_MCF_PREFIX_7, SCRYPT_MCF_PREFIX_s1,
SCRYPT_MCF_PREFIX_ANY) or
_scrypt_ll):
return mcf_mod.scrypt_mcf(scrypt, password, salt, N, r, p, prefix)
s = next(i for i in range(1, 32) if 2**i == N)
t = next(i for i in range(0, 8) if 2**i == p)
m = 2**(10 + s)
o = 2**(5 + t + s)
mcf = ctypes.create_string_buffer(102)
if _scrypt_str(mcf, password, len(password), o, m) != 0:
return mcf_mod.scrypt_mcf(scrypt, password, salt, N, r, p, prefix)
if prefix in (SCRYPT_MCF_PREFIX_7, SCRYPT_MCF_PREFIX_ANY):
return mcf.raw.strip(b'\0')
_N, _r, _p, salt, hash, olen = mcf_mod._scrypt_mcf_decode_7(mcf.raw[:-1])
assert _N == N and _r == r and _p == p, (_N, _r, _p, N, r, p, o, m)
return mcf_mod._scrypt_mcf_encode_s1(N, r, p, salt, hash)
def scrypt_mcf_check(mcf, password):
"""Returns True if the password matches the given MCF hash"""
if mcf_mod._scrypt_mcf_7_is_standard(mcf) and not _scrypt_ll:
return _scrypt_str_chk(mcf, password, len(password)) == 0
return mcf_mod.scrypt_mcf_check(scrypt, mcf, password)
if __name__ == "__main__":
import sys
from . import tests
try:
from . import pylibscrypt
scr_mod = pylibscrypt
except ImportError:
pass
tests.run_scrypt_suite(sys.modules[__name__])