-
Notifications
You must be signed in to change notification settings - Fork 0
/
ecc.py
480 lines (415 loc) · 19.1 KB
/
ecc.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
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
#!/usr/bin/env python
# -*- coding: utf-8 -*-
# Copyright (C) 2011 Yann GUIBET <yannguibet@gmail.com>
# See LICENSE for details.
from hashlib import sha512
from pyelliptic.openssl import OpenSSL
from pyelliptic.cipher import Cipher
from pyelliptic.hash import hmac_sha256, equals
from struct import pack, unpack
class ECC:
"""
Asymmetric encryption with Elliptic Curve Cryptography (ECC)
ECDH, ECDSA and ECIES
import pyelliptic
alice = pyelliptic.ECC() # default curve: sect283r1
bob = pyelliptic.ECC(curve='sect571r1')
ciphertext = alice.encrypt("Hello Bob", bob.get_pubkey())
print bob.decrypt(ciphertext)
signature = bob.sign("Hello Alice")
# alice's job :
print pyelliptic.ECC(
pubkey=bob.get_pubkey()).verify(signature, "Hello Alice")
# ERROR !!!
try:
key = alice.get_ecdh_key(bob.get_pubkey())
except: print("For ECDH key agreement,\
the keys must be defined on the same curve !")
alice = pyelliptic.ECC(curve='sect571r1')
print alice.get_ecdh_key(bob.get_pubkey()).encode('hex')
print bob.get_ecdh_key(alice.get_pubkey()).encode('hex')
"""
def __init__(self, pubkey=None, privkey=None, pubkey_x=None,
pubkey_y=None, raw_privkey=None, curve='sect283r1'):
"""
For a normal and High level use, specifie pubkey,
privkey (if you need) and the curve
"""
if type(curve) == str:
self.curve = OpenSSL.get_curve(curve)
else:
self.curve = curve
if pubkey_x is not None and pubkey_y is not None:
self._set_keys(pubkey_x, pubkey_y, raw_privkey)
elif pubkey is not None:
curve, pubkey_x, pubkey_y, i = ECC._decode_pubkey(pubkey)
if privkey is not None:
curve2, raw_privkey, i = ECC._decode_privkey(privkey)
if curve != curve2:
raise Exception("Bad ECC keys ...")
self.curve = curve
self._set_keys(pubkey_x, pubkey_y, raw_privkey)
else:
self.privkey, self.pubkey_x, self.pubkey_y = self._generate()
def _set_keys(self, pubkey_x, pubkey_y, privkey):
if self.raw_check_key(privkey, pubkey_x, pubkey_y) < 0:
self.pubkey_x = None
self.pubkey_y = None
self.privkey = None
raise Exception("Bad ECC keys ...")
else:
self.pubkey_x = pubkey_x
self.pubkey_y = pubkey_y
self.privkey = privkey
@staticmethod
def get_curves():
"""
static method, returns the list of all the curves available
"""
return OpenSSL.curves.keys()
def get_curve(self):
return OpenSSL.get_curve_by_id(self.curve)
def get_curve_id(self):
return self.curve
def get_pubkey(self):
"""
High level function which returns :
curve(2) + len_of_pubkeyX(2) + pubkeyX + len_of_pubkeyY + pubkeyY
"""
return b''.join((pack('!H', self.curve),
pack('!H', len(self.pubkey_x)),
self.pubkey_x,
pack('!H', len(self.pubkey_y)),
self.pubkey_y
))
def get_privkey(self):
"""
High level function which returns
curve(2) + len_of_privkey(2) + privkey
"""
return b''.join((pack('!H', self.curve),
pack('!H', len(self.privkey)),
self.privkey
))
@staticmethod
def _decode_pubkey(pubkey):
i = 0
curve = unpack('!H', pubkey[i:i + 2])[0]
i += 2
tmplen = unpack('!H', pubkey[i:i + 2])[0]
i += 2
pubkey_x = pubkey[i:i + tmplen]
i += tmplen
tmplen = unpack('!H', pubkey[i:i + 2])[0]
i += 2
pubkey_y = pubkey[i:i + tmplen]
i += tmplen
return curve, pubkey_x, pubkey_y, i
@staticmethod
def _decode_privkey(privkey):
i = 0
curve = unpack('!H', privkey[i:i + 2])[0]
i += 2
tmplen = unpack('!H', privkey[i:i + 2])[0]
i += 2
privkey = privkey[i:i + tmplen]
i += tmplen
return curve, privkey, i
def _generate(self):
try:
pub_key_x = OpenSSL.BN_new()
pub_key_y = OpenSSL.BN_new()
key = OpenSSL.EC_KEY_new_by_curve_name(self.curve)
if key == 0:
raise Exception("[OpenSSL] EC_KEY_new_by_curve_name FAIL ...")
if (OpenSSL.EC_KEY_generate_key(key)) == 0:
raise Exception("[OpenSSL] EC_KEY_generate_key FAIL ...")
if (OpenSSL.EC_KEY_check_key(key)) == 0:
raise Exception("[OpenSSL] EC_KEY_check_key FAIL ...")
priv_key = OpenSSL.EC_KEY_get0_private_key(key)
group = OpenSSL.EC_KEY_get0_group(key)
pub_key = OpenSSL.EC_KEY_get0_public_key(key)
if (OpenSSL.EC_POINT_get_affine_coordinates_GFp(group, pub_key,
pub_key_x,
pub_key_y, 0
)) == 0:
raise Exception(
"[OpenSSL] EC_POINT_get_affine_coordinates_GFp FAIL ...")
privkey = OpenSSL.malloc(0, OpenSSL.BN_num_bytes(priv_key))
pubkeyx = OpenSSL.malloc(0, OpenSSL.BN_num_bytes(pub_key_x))
pubkeyy = OpenSSL.malloc(0, OpenSSL.BN_num_bytes(pub_key_y))
OpenSSL.BN_bn2bin(priv_key, privkey)
privkey = privkey.raw
OpenSSL.BN_bn2bin(pub_key_x, pubkeyx)
pubkeyx = pubkeyx.raw
OpenSSL.BN_bn2bin(pub_key_y, pubkeyy)
pubkeyy = pubkeyy.raw
self.raw_check_key(privkey, pubkeyx, pubkeyy)
return privkey, pubkeyx, pubkeyy
finally:
OpenSSL.EC_KEY_free(key)
OpenSSL.BN_free(pub_key_x)
OpenSSL.BN_free(pub_key_y)
def get_ecdh_key(self, pubkey):
"""
High level function. Compute public key with the local private key
and returns a 512bits shared key
"""
curve, pubkey_x, pubkey_y, i = ECC._decode_pubkey(pubkey)
if curve != self.curve:
raise Exception("ECC keys must be from the same curve !")
return sha512(self.raw_get_ecdh_key(pubkey_x, pubkey_y)).digest()
def raw_get_ecdh_key(self, pubkey_x, pubkey_y):
try:
ecdh_keybuffer = OpenSSL.malloc(0, 32)
other_key = OpenSSL.EC_KEY_new_by_curve_name(self.curve)
if other_key == 0:
raise Exception("[OpenSSL] EC_KEY_new_by_curve_name FAIL ...")
other_pub_key_x = OpenSSL.BN_bin2bn(pubkey_x, len(pubkey_x), 0)
other_pub_key_y = OpenSSL.BN_bin2bn(pubkey_y, len(pubkey_y), 0)
other_group = OpenSSL.EC_KEY_get0_group(other_key)
other_pub_key = OpenSSL.EC_POINT_new(other_group)
if (OpenSSL.EC_POINT_set_affine_coordinates_GFp(other_group,
other_pub_key,
other_pub_key_x,
other_pub_key_y,
0)) == 0:
raise Exception(
"[OpenSSL] EC_POINT_set_affine_coordinates_GFp FAIL ...")
if (OpenSSL.EC_KEY_set_public_key(other_key, other_pub_key)) == 0:
raise Exception("[OpenSSL] EC_KEY_set_public_key FAIL ...")
if (OpenSSL.EC_KEY_check_key(other_key)) == 0:
raise Exception("[OpenSSL] EC_KEY_check_key FAIL ...")
own_key = OpenSSL.EC_KEY_new_by_curve_name(self.curve)
if own_key == 0:
raise Exception("[OpenSSL] EC_KEY_new_by_curve_name FAIL ...")
own_priv_key = OpenSSL.BN_bin2bn(
self.privkey, len(self.privkey), 0)
if (OpenSSL.EC_KEY_set_private_key(own_key, own_priv_key)) == 0:
raise Exception("[OpenSSL] EC_KEY_set_private_key FAIL ...")
if OpenSSL._hexversion > 0x10100000 and not OpenSSL._libreSSL:
OpenSSL.EC_KEY_set_method(own_key, OpenSSL.EC_KEY_OpenSSL())
else:
OpenSSL.ECDH_set_method(own_key, OpenSSL.ECDH_OpenSSL())
ecdh_keylen = OpenSSL.ECDH_compute_key(
ecdh_keybuffer, 32, other_pub_key, own_key, 0)
if ecdh_keylen != 32:
raise Exception("[OpenSSL] ECDH keylen FAIL ...")
return ecdh_keybuffer.raw
finally:
OpenSSL.EC_KEY_free(other_key)
OpenSSL.BN_free(other_pub_key_x)
OpenSSL.BN_free(other_pub_key_y)
OpenSSL.EC_POINT_free(other_pub_key)
OpenSSL.EC_KEY_free(own_key)
OpenSSL.BN_free(own_priv_key)
def check_key(self, privkey, pubkey):
"""
Check the public key and the private key.
The private key is optional (replace by None)
"""
curve, pubkey_x, pubkey_y, i = ECC._decode_pubkey(pubkey)
if privkey is None:
raw_privkey = None
curve2 = curve
else:
curve2, raw_privkey, i = ECC._decode_privkey(privkey)
if curve != curve2:
raise Exception("Bad public and private key")
return self.raw_check_key(raw_privkey, pubkey_x, pubkey_y, curve)
def raw_check_key(self, privkey, pubkey_x, pubkey_y, curve=None):
if curve is None:
curve = self.curve
elif type(curve) == str:
curve = OpenSSL.get_curve(curve)
else:
curve = curve
try:
key = OpenSSL.EC_KEY_new_by_curve_name(curve)
if key == 0:
raise Exception("[OpenSSL] EC_KEY_new_by_curve_name FAIL ...")
if privkey is not None:
priv_key = OpenSSL.BN_bin2bn(privkey, len(privkey), 0)
pub_key_x = OpenSSL.BN_bin2bn(pubkey_x, len(pubkey_x), 0)
pub_key_y = OpenSSL.BN_bin2bn(pubkey_y, len(pubkey_y), 0)
if privkey is not None:
if (OpenSSL.EC_KEY_set_private_key(key, priv_key)) == 0:
raise Exception(
"[OpenSSL] EC_KEY_set_private_key FAIL ...")
group = OpenSSL.EC_KEY_get0_group(key)
pub_key = OpenSSL.EC_POINT_new(group)
if (OpenSSL.EC_POINT_set_affine_coordinates_GFp(group, pub_key,
pub_key_x,
pub_key_y,
0)) == 0:
raise Exception(
"[OpenSSL] EC_POINT_set_affine_coordinates_GFp FAIL ...")
if (OpenSSL.EC_KEY_set_public_key(key, pub_key)) == 0:
raise Exception("[OpenSSL] EC_KEY_set_public_key FAIL ...")
if (OpenSSL.EC_KEY_check_key(key)) == 0:
raise Exception("[OpenSSL] EC_KEY_check_key FAIL ...")
return 0
finally:
OpenSSL.EC_KEY_free(key)
OpenSSL.BN_free(pub_key_x)
OpenSSL.BN_free(pub_key_y)
OpenSSL.EC_POINT_free(pub_key)
if privkey is not None:
OpenSSL.BN_free(priv_key)
def sign(self, inputb, digest_alg=OpenSSL.digest_ecdsa_sha1):
"""
Sign the input with ECDSA method and returns the signature
"""
try:
size = len(inputb)
buff = OpenSSL.malloc(inputb, size)
digest = OpenSSL.malloc(0, 64)
if OpenSSL._hexversion > 0x10100000 and not OpenSSL._libreSSL:
md_ctx = OpenSSL.EVP_MD_CTX_new()
else:
md_ctx = OpenSSL.EVP_MD_CTX_create()
dgst_len = OpenSSL.pointer(OpenSSL.c_int(0))
siglen = OpenSSL.pointer(OpenSSL.c_int(0))
sig = OpenSSL.malloc(0, 151)
key = OpenSSL.EC_KEY_new_by_curve_name(self.curve)
if key == 0:
raise Exception("[OpenSSL] EC_KEY_new_by_curve_name FAIL ...")
priv_key = OpenSSL.BN_bin2bn(self.privkey, len(self.privkey), 0)
pub_key_x = OpenSSL.BN_bin2bn(self.pubkey_x, len(self.pubkey_x), 0)
pub_key_y = OpenSSL.BN_bin2bn(self.pubkey_y, len(self.pubkey_y), 0)
if (OpenSSL.EC_KEY_set_private_key(key, priv_key)) == 0:
raise Exception("[OpenSSL] EC_KEY_set_private_key FAIL ...")
group = OpenSSL.EC_KEY_get0_group(key)
pub_key = OpenSSL.EC_POINT_new(group)
if (OpenSSL.EC_POINT_set_affine_coordinates_GFp(group, pub_key,
pub_key_x,
pub_key_y,
0)) == 0:
raise Exception(
"[OpenSSL] EC_POINT_set_affine_coordinates_GFp FAIL ...")
if (OpenSSL.EC_KEY_set_public_key(key, pub_key)) == 0:
raise Exception("[OpenSSL] EC_KEY_set_public_key FAIL ...")
if (OpenSSL.EC_KEY_check_key(key)) == 0:
raise Exception("[OpenSSL] EC_KEY_check_key FAIL ...")
if OpenSSL._hexversion > 0x10100000 and not OpenSSL._libreSSL:
OpenSSL.EVP_MD_CTX_new(md_ctx)
else:
OpenSSL.EVP_MD_CTX_init(md_ctx)
OpenSSL.EVP_DigestInit_ex(md_ctx, digest_alg(), None)
if (OpenSSL.EVP_DigestUpdate(md_ctx, buff, size)) == 0:
raise Exception("[OpenSSL] EVP_DigestUpdate FAIL ...")
OpenSSL.EVP_DigestFinal_ex(md_ctx, digest, dgst_len)
OpenSSL.ECDSA_sign(0, digest, dgst_len.contents, sig, siglen, key)
if (OpenSSL.ECDSA_verify(0, digest, dgst_len.contents, sig,
siglen.contents, key)) != 1:
raise Exception("[OpenSSL] ECDSA_verify FAIL ...")
return sig.raw[:siglen.contents.value]
finally:
OpenSSL.EC_KEY_free(key)
OpenSSL.BN_free(pub_key_x)
OpenSSL.BN_free(pub_key_y)
OpenSSL.BN_free(priv_key)
OpenSSL.EC_POINT_free(pub_key)
if OpenSSL._hexversion > 0x10100000 and not OpenSSL._libreSSL:
OpenSSL.EVP_MD_CTX_free(md_ctx)
else:
OpenSSL.EVP_MD_CTX_destroy(md_ctx)
pass
def verify(self, sig, inputb, digest_alg=OpenSSL.digest_ecdsa_sha1):
"""
Verify the signature with the input and the local public key.
Returns a boolean
"""
try:
bsig = OpenSSL.malloc(sig, len(sig))
binputb = OpenSSL.malloc(inputb, len(inputb))
digest = OpenSSL.malloc(0, 64)
dgst_len = OpenSSL.pointer(OpenSSL.c_int(0))
if OpenSSL._hexversion > 0x10100000 and not OpenSSL._libreSSL:
md_ctx = OpenSSL.EVP_MD_CTX_new()
else:
md_ctx = OpenSSL.EVP_MD_CTX_create()
key = OpenSSL.EC_KEY_new_by_curve_name(self.curve)
if key == 0:
raise Exception("[OpenSSL] EC_KEY_new_by_curve_name FAIL ...")
pub_key_x = OpenSSL.BN_bin2bn(self.pubkey_x, len(self.pubkey_x), 0)
pub_key_y = OpenSSL.BN_bin2bn(self.pubkey_y, len(self.pubkey_y), 0)
group = OpenSSL.EC_KEY_get0_group(key)
pub_key = OpenSSL.EC_POINT_new(group)
if (OpenSSL.EC_POINT_set_affine_coordinates_GFp(group, pub_key,
pub_key_x,
pub_key_y,
0)) == 0:
raise Exception(
"[OpenSSL] EC_POINT_set_affine_coordinates_GFp FAIL ...")
if (OpenSSL.EC_KEY_set_public_key(key, pub_key)) == 0:
raise Exception("[OpenSSL] EC_KEY_set_public_key FAIL ...")
if (OpenSSL.EC_KEY_check_key(key)) == 0:
raise Exception("[OpenSSL] EC_KEY_check_key FAIL ...")
if OpenSSL._hexversion > 0x10100000 and not OpenSSL._libreSSL:
OpenSSL.EVP_MD_CTX_new(md_ctx)
else:
OpenSSL.EVP_MD_CTX_init(md_ctx)
OpenSSL.EVP_DigestInit_ex(md_ctx, digest_alg(), None)
if (OpenSSL.EVP_DigestUpdate(md_ctx, binputb, len(inputb))) == 0:
raise Exception("[OpenSSL] EVP_DigestUpdate FAIL ...")
OpenSSL.EVP_DigestFinal_ex(md_ctx, digest, dgst_len)
ret = OpenSSL.ECDSA_verify(
0, digest, dgst_len.contents, bsig, len(sig), key)
if ret == -1:
return False # Fail to Check
else:
if ret == 0:
return False # Bad signature !
else:
return True # Good
return False
finally:
OpenSSL.EC_KEY_free(key)
OpenSSL.BN_free(pub_key_x)
OpenSSL.BN_free(pub_key_y)
OpenSSL.EC_POINT_free(pub_key)
if OpenSSL._hexversion > 0x10100000 and not OpenSSL._libreSSL:
OpenSSL.EVP_MD_CTX_free(md_ctx)
else:
OpenSSL.EVP_MD_CTX_destroy(md_ctx)
@staticmethod
def encrypt(data, pubkey, ephemcurve=None, ciphername='aes-256-cbc'):
"""
Encrypt data with ECIES method using the public key of the recipient.
"""
curve, pubkey_x, pubkey_y, i = ECC._decode_pubkey(pubkey)
return ECC.raw_encrypt(data, pubkey_x, pubkey_y, curve=curve,
ephemcurve=ephemcurve, ciphername=ciphername)
@staticmethod
def raw_encrypt(data, pubkey_x, pubkey_y, curve='sect283r1',
ephemcurve=None, ciphername='aes-256-cbc'):
if ephemcurve is None:
ephemcurve = curve
ephem = ECC(curve=ephemcurve)
key = sha512(ephem.raw_get_ecdh_key(pubkey_x, pubkey_y)).digest()
key_e, key_m = key[:32], key[32:]
pubkey = ephem.get_pubkey()
iv = OpenSSL.rand(OpenSSL.get_cipher(ciphername).get_blocksize())
ctx = Cipher(key_e, iv, 1, ciphername)
ciphertext = iv + pubkey + ctx.ciphering(data)
mac = hmac_sha256(key_m, ciphertext)
return ciphertext + mac
def decrypt(self, data, ciphername='aes-256-cbc'):
"""
Decrypt data with ECIES method using the local private key
"""
blocksize = OpenSSL.get_cipher(ciphername).get_blocksize()
iv = data[:blocksize]
i = blocksize
curve, pubkey_x, pubkey_y, i2 = ECC._decode_pubkey(data[i:])
i += i2
ciphertext = data[i:len(data)-32]
i += len(ciphertext)
mac = data[i:]
key = sha512(self.raw_get_ecdh_key(pubkey_x, pubkey_y)).digest()
key_e, key_m = key[:32], key[32:]
if not equals(hmac_sha256(key_m, data[:len(data) - 32]), mac):
raise RuntimeError("Fail to verify data")
ctx = Cipher(key_e, iv, 0, ciphername)
return ctx.ciphering(ciphertext)