-
Notifications
You must be signed in to change notification settings - Fork 8
/
crypto.py
291 lines (238 loc) · 14.3 KB
/
crypto.py
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
#!/usr/bin/env python3
# -*- coding: utf-8 -*-
""" This module defines cryptographic classes
"""
import hashlib
import os
from hmac import HMAC
import cryptography.hazmat.backends.openssl.backend
from cryptography.exceptions import InvalidSignature
from cryptography.hazmat.backends import default_backend
from cryptography.hazmat.primitives import serialization, hashes
from cryptography.hazmat.primitives.asymmetric import dh, padding, ec
from cryptography.hazmat.primitives.ciphers import Cipher as _Cipher, algorithms, modes
from message import Transform, InvalidSyntax
__author__ = 'Alejandro Perez-Mendez <alejandro.perez.mendez@gmail.com>'
class EncrError(Exception):
pass
class Prf(object):
_digestmod_dict = {
Transform.PrfId.PRF_HMAC_SHA1: hashlib.sha1,
Transform.PrfId.PRF_HMAC_SHA2_256: hashlib.sha256,
Transform.PrfId.PRF_HMAC_SHA2_512: hashlib.sha512,
}
def __init__(self, transform):
assert(transform.type == Transform.Type.PRF)
self.hasher = self._digestmod_dict[transform.id]
@property
def key_size(self):
return self.hash_size
@property
def hash_size(self):
return self.hasher().digest_size
def prf(self, key, data):
m = HMAC(key, data, digestmod=self.hasher)
return m.digest()
def prfplus(self, key, seed, size):
result = bytes()
temp = bytes()
i = 1
while len(result) < size:
temp = self.prf(key, temp + seed + i.to_bytes(1, 'big'))
result += temp
i += 1
return result[:size]
class Cipher:
_algorithm_dict = {
Transform.EncrId.ENCR_AES_CBC: algorithms.AES,
}
_backend = cryptography.hazmat.backends.openssl.backend
def __init__(self, transform):
assert(transform.type == Transform.Type.ENCR)
self._algorithm = self._algorithm_dict[transform.id]
self._transform = transform
# establish whether transform.keylen attribute is valid
if self._transform.keylen is not None:
if len(self._algorithm.key_sizes) == 1:
raise InvalidSyntax(
f'Algorithm {self._algorithm.name} only accepts one keylen but KEY_LEN attribute is provided.')
if transform.keylen not in self._algorithm.key_sizes:
raise InvalidSyntax(f'Incorrect key length {transform.keylen} for algorithm {self._algorithm.name}. '
f'Acceptable values are: {self._algorithm.key_sizes}')
elif len(self._algorithm.key_sizes) > 1:
raise('Algorithm {} requires a KEY_LEN attribute'.format(self._algorithm.name))
@property
def block_size(self):
return self._algorithm.block_size // 8
@property
def key_size(self):
# if no KEYLEN attribute is present, return the first possible one
return (self._transform.keylen or self._algorithm.key_sizes[0]) // 8
def encrypt(self, key, iv, data):
if len(key) != self.key_size:
raise EncrError('Key must be of the indicated size {}'.format(self.key_size))
_cipher = _Cipher(self._algorithm(key), modes.CBC(iv), backend=self._backend)
encryptor = _cipher.encryptor()
return encryptor.update(data) + encryptor.finalize()
def decrypt(self, key, iv, data):
if len(key) != self.key_size:
raise EncrError('Key must be of the indicated size {}'.format(self.key_size))
_cipher = _Cipher(self._algorithm(key), modes.CBC(iv), backend=self._backend)
decryptor = _cipher.decryptor()
return decryptor.update(data) + decryptor.finalize()
def generate_iv(self):
return os.urandom(self.block_size)
class MODPDH:
_group_dict = {
Transform.DhId.DH_14: # MODP2048
'FFFFFFFFFFFFFFFFC90FDAA22168C234C4C6628B80DC1CD129024E088A67CC74020BBEA63B139B22514A08798E3404DDEF9519B3C'
'D3A431B302B0A6DF25F14374FE1356D6D51C245E485B576625E7EC6F44C42E9A637ED6B0BFF5CB6F406B7EDEE386BFB5A899FA5AE'
'9F24117C4B1FE649286651ECE45B3DC2007CB8A163BF0598DA48361C55D39A69163FA8FD24CF5F83655D23DCA3AD961C62F356208'
'552BB9ED529077096966D670C354E4ABC9804F1746C08CA18217C32905E462E36CE3BE39E772C180E86039B2783A2EC07A28FB5C5'
'5DF06F4C52C9DE2BCBF6955817183995497CEA956AE515D2261898FA051015728E5A8AACAA68FFFFFFFFFFFFFFFF',
Transform.DhId.DH_15: # MODP3072
'FFFFFFFFFFFFFFFFC90FDAA22168C234C4C6628B80DC1CD129024E088A67CC74020BBEA63B139B22514A08798E3404DDEF9519B3C'
'D3A431B302B0A6DF25F14374FE1356D6D51C245E485B576625E7EC6F44C42E9A637ED6B0BFF5CB6F406B7EDEE386BFB5A899FA5AE'
'9F24117C4B1FE649286651ECE45B3DC2007CB8A163BF0598DA48361C55D39A69163FA8FD24CF5F83655D23DCA3AD961C62F356208'
'552BB9ED529077096966D670C354E4ABC9804F1746C08CA18217C32905E462E36CE3BE39E772C180E86039B2783A2EC07A28FB5C5'
'5DF06F4C52C9DE2BCBF6955817183995497CEA956AE515D2261898FA051015728E5A8AAAC42DAD33170D04507A33A85521ABDF1CB'
'A64ECFB850458DBEF0A8AEA71575D060C7DB3970F85A6E1E4C7ABF5AE8CDB0933D71E8C94E04A25619DCEE3D2261AD2EE6BF12FFA'
'06D98A0864D87602733EC86A64521F2B18177B200CBBE117577A615D6C770988C0BAD946E208E24FA074E5AB3143DB5BFCE0FD108'
'E4B82D120A93AD2CAFFFFFFFFFFFFFFFF',
Transform.DhId.DH_16: # MODP4096
'FFFFFFFFFFFFFFFFC90FDAA22168C234C4C6628B80DC1CD129024E088A67CC74020BBEA63B139B22514A08798E3404DDEF9519B3C'
'D3A431B302B0A6DF25F14374FE1356D6D51C245E485B576625E7EC6F44C42E9A637ED6B0BFF5CB6F406B7EDEE386BFB5A899FA5AE'
'9F24117C4B1FE649286651ECE45B3DC2007CB8A163BF0598DA48361C55D39A69163FA8FD24CF5F83655D23DCA3AD961C62F356208'
'552BB9ED529077096966D670C354E4ABC9804F1746C08CA18217C32905E462E36CE3BE39E772C180E86039B2783A2EC07A28FB5C5'
'5DF06F4C52C9DE2BCBF6955817183995497CEA956AE515D2261898FA051015728E5A8AAAC42DAD33170D04507A33A85521ABDF1CB'
'A64ECFB850458DBEF0A8AEA71575D060C7DB3970F85A6E1E4C7ABF5AE8CDB0933D71E8C94E04A25619DCEE3D2261AD2EE6BF12FFA'
'06D98A0864D87602733EC86A64521F2B18177B200CBBE117577A615D6C770988C0BAD946E208E24FA074E5AB3143DB5BFCE0FD108'
'E4B82D120A92108011A723C12A787E6D788719A10BDBA5B2699C327186AF4E23C1A946834B6150BDA2583E9CA2AD44CE8DBBBC2DB'
'04DE8EF92E8EFC141FBECAA6287C59474E6BC05D99B2964FA090C3A2233BA186515BE7ED1F612970CEE2D7AFB81BDD762170481CD'
'0069127D5B05AA993B4EA988D8FDDC186FFB7DC90A6C08F4DF435C934063199FFFFFFFFFFFFFFFF',
Transform.DhId.DH_17: # MODP6144
'FFFFFFFFFFFFFFFFC90FDAA22168C234C4C6628B80DC1CD129024E088A67CC74020BBEA63B139B22514A08798E3404DDEF9519B3C'
'D3A431B302B0A6DF25F14374FE1356D6D51C245E485B576625E7EC6F44C42E9A637ED6B0BFF5CB6F406B7EDEE386BFB5A899FA5AE'
'9F24117C4B1FE649286651ECE45B3DC2007CB8A163BF0598DA48361C55D39A69163FA8FD24CF5F83655D23DCA3AD961C62F356208'
'552BB9ED529077096966D670C354E4ABC9804F1746C08CA18217C32905E462E36CE3BE39E772C180E86039B2783A2EC07A28FB5C5'
'5DF06F4C52C9DE2BCBF6955817183995497CEA956AE515D2261898FA051015728E5A8AAAC42DAD33170D04507A33A85521ABDF1CB'
'A64ECFB850458DBEF0A8AEA71575D060C7DB3970F85A6E1E4C7ABF5AE8CDB0933D71E8C94E04A25619DCEE3D2261AD2EE6BF12FFA'
'06D98A0864D87602733EC86A64521F2B18177B200CBBE117577A615D6C770988C0BAD946E208E24FA074E5AB3143DB5BFCE0FD108'
'E4B82D120A92108011A723C12A787E6D788719A10BDBA5B2699C327186AF4E23C1A946834B6150BDA2583E9CA2AD44CE8DBBBC2DB'
'04DE8EF92E8EFC141FBECAA6287C59474E6BC05D99B2964FA090C3A2233BA186515BE7ED1F612970CEE2D7AFB81BDD762170481CD'
'0069127D5B05AA993B4EA988D8FDDC186FFB7DC90A6C08F4DF435C93402849236C3FAB4D27C7026C1D4DCB2602646DEC9751E763D'
'BA37BDF8FF9406AD9E530EE5DB382F413001AEB06A53ED9027D831179727B0865A8918DA3EDBEBCF9B14ED44CE6CBACED4BB1BDB7'
'F1447E6CC254B332051512BD7AF426FB8F401378CD2BF5983CA01C64B92ECF032EA15D1721D03F482D7CE6E74FEF6D55E702F4698'
'0C82B5A84031900B1C9E59E7C97FBEC7E8F323A97A7E36CC88BE0F1D45B7FF585AC54BD407B22B4154AACC8F6D7EBF48E1D814CC5'
'ED20F8037E0A79715EEF29BE32806A1D58BB7C5DA76F550AA3D8A1FBFF0EB19CCB1A313D55CDA56C9EC2EF29632387FE8D76E3C04'
'68043E8F663F4860EE12BF2D5B0B7474D6E694F91E6DCC4024FFFFFFFFFFFFFFFF',
Transform.DhId.DH_18: # MODP8192
'FFFFFFFFFFFFFFFFC90FDAA22168C234C4C6628B80DC1CD129024E088A67CC74020BBEA63B139B22514A08798E3404DD'
'EF9519B3CD3A431B302B0A6DF25F14374FE1356D6D51C245E485B576625E7EC6F44C42E9A637ED6B0BFF5CB6F406B7ED'
'EE386BFB5A899FA5AE9F24117C4B1FE649286651ECE45B3DC2007CB8A163BF0598DA48361C55D39A69163FA8FD24CF5F'
'83655D23DCA3AD961C62F356208552BB9ED529077096966D670C354E4ABC9804F1746C08CA18217C32905E462E36CE3B'
'E39E772C180E86039B2783A2EC07A28FB5C55DF06F4C52C9DE2BCBF6955817183995497CEA956AE515D2261898FA0510'
'15728E5A8AAAC42DAD33170D04507A33A85521ABDF1CBA64ECFB850458DBEF0A8AEA71575D060C7DB3970F85A6E1E4C7'
'ABF5AE8CDB0933D71E8C94E04A25619DCEE3D2261AD2EE6BF12FFA06D98A0864D87602733EC86A64521F2B18177B200C'
'BBE117577A615D6C770988C0BAD946E208E24FA074E5AB3143DB5BFCE0FD108E4B82D120A92108011A723C12A787E6D7'
'88719A10BDBA5B2699C327186AF4E23C1A946834B6150BDA2583E9CA2AD44CE8DBBBC2DB04DE8EF92E8EFC141FBECAA6'
'287C59474E6BC05D99B2964FA090C3A2233BA186515BE7ED1F612970CEE2D7AFB81BDD762170481CD0069127D5B05AA9'
'93B4EA988D8FDDC186FFB7DC90A6C08F4DF435C93402849236C3FAB4D27C7026C1D4DCB2602646DEC9751E763DBA37BD'
'F8FF9406AD9E530EE5DB382F413001AEB06A53ED9027D831179727B0865A8918DA3EDBEBCF9B14ED44CE6CBACED4BB1B'
'DB7F1447E6CC254B332051512BD7AF426FB8F401378CD2BF5983CA01C64B92ECF032EA15D1721D03F482D7CE6E74FEF6'
'D55E702F46980C82B5A84031900B1C9E59E7C97FBEC7E8F323A97A7E36CC88BE0F1D45B7FF585AC54BD407B22B4154AA'
'CC8F6D7EBF48E1D814CC5ED20F8037E0A79715EEF29BE32806A1D58BB7C5DA76F550AA3D8A1FBFF0EB19CCB1A313D55C'
'DA56C9EC2EF29632387FE8D76E3C0468043E8F663F4860EE12BF2D5B0B7474D6E694F91E6DBE115974A3926F12FEE5E4'
'38777CB6A932DF8CD8BEC4D073B931BA3BC832B68D9DD300741FA7BF8AFC47ED2576F6936BA424663AAB639C5AE4F568'
'3423B4742BF1C978238F16CBE39D652DE3FDB8BEFC848AD922222E04A4037C0713EB57A81A23F0C73473FC646CEA306B'
'4BCBC8862F8385DDFA9D4B7FA2C087E879683303ED5BDD3A062B3CF5B3A278A66D2A13F83F44F82DDF310EE074AB6A36'
'4597E899A0255DC164F31CC50846851DF9AB48195DED7EA1B1D510BD7EE74D73FAF36BC31ECFA268359046F4EB879F92'
'4009438B481C6CD7889A002ED5EE382BC9190DA6FC026E479558E4475677E9AA9E3050E2765694DFC81F56E880B96E71'
'60C980DD98EDD3DFFFFFFFFFFFFFFFFF',
}
backend = cryptography.hazmat.backends.openssl.backend
def __init__(self, group):
self.group = group
self.key_len = len(self._group_dict[group]) // 2
module = int(self._group_dict[self.group], 16)
self._pn = dh.DHParameterNumbers(module, 2)
self._parameters = self._pn.parameters(self.backend)
self.shared_secret = None
self._private_key = self._parameters.generate_private_key()
public_key_int = self._private_key.public_key().public_numbers().y
self.public_key = public_key_int.to_bytes(self.key_len, 'big')
def compute_secret(self, peer_public_key):
peer_public_key_int = int.from_bytes(peer_public_key, 'big')
peer_public_numbers = dh.DHPublicNumbers(peer_public_key_int, self._pn)
peer_public_key = peer_public_numbers.public_key(self.backend)
self.shared_secret = self._private_key.exchange(peer_public_key)
class ECDH:
_ec_groups = {
Transform.DhId.DH_19: ec.SECP256R1(),
Transform.DhId.DH_20: ec.SECP384R1(),
Transform.DhId.DH_21: ec.SECP521R1(),
}
backend = cryptography.hazmat.backends.openssl.backend
def __init__(self, group):
self.group = group
self._private_key = ec.generate_private_key(self._ec_groups[group], backend=self.backend)
# Trick to get the ceil of the division
self.key_len = (self._private_key.key_size + 7) // 8
self.shared_secret = None
public_numbers = self._private_key.public_key().public_numbers()
self.public_key = (public_numbers.x.to_bytes(self.key_len, 'big')
+ public_numbers.y.to_bytes(self.key_len, 'big'))
def compute_secret(self, peer_public_key):
x = int.from_bytes(peer_public_key[:self.key_len], 'big')
y = int.from_bytes(peer_public_key[self.key_len:], 'big')
peer_public_numbers = ec.EllipticCurvePublicNumbers(x, y, self._ec_groups[self.group])
peer_public_key = peer_public_numbers.public_key(self.backend)
self.shared_secret = self._private_key.exchange(ec.ECDH(), peer_public_key)
class DiffieHellman:
@classmethod
def from_group(cls, group):
try:
return MODPDH(group)
except KeyError:
return ECDH(group)
class Integrity:
_digestmod_dict = {
Transform.IntegId.AUTH_HMAC_SHA1_96: (hashlib.sha1, 96),
Transform.IntegId.AUTH_HMAC_SHA2_256_128: (hashlib.sha256, 128),
Transform.IntegId.AUTH_HMAC_SHA2_512_256: (hashlib.sha512, 256),
}
def __init__(self, transform):
assert(transform.type == Transform.Type.INTEG)
self.hasher, self.keybits = self._digestmod_dict[transform.id]
@property
def key_size(self):
return self.hasher().digest_size
@property
def hash_size(self):
# Hardcoded as we only support _96 algorithms so far
return self.keybits // 8
def compute(self, key, data):
m = HMAC(key, data, digestmod=self.hasher)
return m.digest()[:self.hash_size]
class Crypto:
def __init__(self, cipher, sk_e, integrity, sk_a, prf, sk_p):
self.cipher = cipher
self.sk_e = sk_e
self.integrity = integrity
self.sk_a = sk_a
self.prf = prf
self.sk_p = sk_p
class RsaPrivateKey:
def __init__(self, pem):
self.key = serialization.load_pem_private_key(pem, password=None, backend=default_backend())
def sign(self, data):
return self.key.sign(data, padding.PKCS1v15(), hashes.SHA256())
class RsaPublicKey:
def __init__(self, pem):
self.key = serialization.load_pem_public_key(pem, backend=default_backend())
def verify(self, signature, data):
try:
self.key.verify(signature, data, padding.PKCS1v15(), hashes.SHA256())
return True
except InvalidSignature:
return False