Current File : //var/opt/nydus/ops/oscrypto/_pkcs12.py
# coding: utf-8
from __future__ import unicode_literals, division, absolute_import, print_function
import sys
import hashlib
import math
from ._asn1 import int_from_bytes, int_to_bytes
from ._errors import pretty_message
from ._types import type_name, byte_cls, int_types
if sys.version_info < (3,):
chr_cls = chr
else:
def chr_cls(num):
return bytes([num])
__all__ = [
'pkcs12_kdf',
]
def pkcs12_kdf(hash_algorithm, password, salt, iterations, key_length, id_):
"""
KDF from RFC7292 appendix b.2 - https://tools.ietf.org/html/rfc7292#page-19
:param hash_algorithm:
The string name of the hash algorithm to use: "md5", "sha1", "sha224",
"sha256", "sha384", "sha512"
:param password:
A byte string of the password to use an input to the KDF
:param salt:
A cryptographic random byte string
:param iterations:
The numbers of iterations to use when deriving the key
:param key_length:
The length of the desired key in bytes
:param id_:
The ID of the usage - 1 for key, 2 for iv, 3 for mac
:return:
The derived key as a byte string
"""
if not isinstance(password, byte_cls):
raise TypeError(pretty_message(
'''
password must be a byte string, not %s
''',
type_name(password)
))
if not isinstance(salt, byte_cls):
raise TypeError(pretty_message(
'''
salt must be a byte string, not %s
''',
type_name(salt)
))
if not isinstance(iterations, int_types):
raise TypeError(pretty_message(
'''
iterations must be an integer, not %s
''',
type_name(iterations)
))
if iterations < 1:
raise ValueError(pretty_message(
'''
iterations must be greater than 0 - is %s
''',
repr(iterations)
))
if not isinstance(key_length, int_types):
raise TypeError(pretty_message(
'''
key_length must be an integer, not %s
''',
type_name(key_length)
))
if key_length < 1:
raise ValueError(pretty_message(
'''
key_length must be greater than 0 - is %s
''',
repr(key_length)
))
if hash_algorithm not in set(['md5', 'sha1', 'sha224', 'sha256', 'sha384', 'sha512']):
raise ValueError(pretty_message(
'''
hash_algorithm must be one of "md5", "sha1", "sha224", "sha256",
"sha384", "sha512", not %s
''',
repr(hash_algorithm)
))
if id_ not in set([1, 2, 3]):
raise ValueError(pretty_message(
'''
id_ must be one of 1, 2, 3, not %s
''',
repr(id_)
))
utf16_password = password.decode('utf-8').encode('utf-16be') + b'\x00\x00'
algo = getattr(hashlib, hash_algorithm)
# u and v values are bytes (not bits as in the RFC)
u = {
'md5': 16,
'sha1': 20,
'sha224': 28,
'sha256': 32,
'sha384': 48,
'sha512': 64
}[hash_algorithm]
if hash_algorithm in ['sha384', 'sha512']:
v = 128
else:
v = 64
# Step 1
d = chr_cls(id_) * v
# Step 2
s = b''
if salt != b'':
s_len = v * int(math.ceil(float(len(salt)) / v))
while len(s) < s_len:
s += salt
s = s[0:s_len]
# Step 3
p = b''
if utf16_password != b'':
p_len = v * int(math.ceil(float(len(utf16_password)) / v))
while len(p) < p_len:
p += utf16_password
p = p[0:p_len]
# Step 4
i = s + p
# Step 5
c = int(math.ceil(float(key_length) / u))
a = b'\x00' * (c * u)
for num in range(1, c + 1):
# Step 6A
a2 = algo(d + i).digest()
for _ in range(2, iterations + 1):
a2 = algo(a2).digest()
if num < c:
# Step 6B
b = b''
while len(b) < v:
b += a2
b = int_from_bytes(b[0:v]) + 1
# Step 6C
for num2 in range(0, len(i) // v):
start = num2 * v
end = (num2 + 1) * v
i_num2 = i[start:end]
i_num2 = int_to_bytes(int_from_bytes(i_num2) + b)
# Ensure the new slice is the right size
i_num2_l = len(i_num2)
if i_num2_l > v:
i_num2 = i_num2[i_num2_l - v:]
i = i[0:start] + i_num2 + i[end:]
# Step 7 (one piece at a time)
begin = (num - 1) * u
to_copy = min(key_length, u)
a = a[0:begin] + a2[0:to_copy] + a[begin + to_copy:]
return a[0:key_length]
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