forked from trustcrypto/python-onlykey
-
Notifications
You must be signed in to change notification settings - Fork 0
Expand file tree
/
Copy pathecdh_p256.py
More file actions
executable file
·170 lines (138 loc) · 5.33 KB
/
ecdh_p256.py
File metadata and controls
executable file
·170 lines (138 loc) · 5.33 KB
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
# coding: utf-8
import hashlib
import time
import os
from binascii import hexlify
import pyelliptic
from onlykey import OnlyKey, Message
print 'Generating a new NIST P-256 key pair...'
# Asymmetric encryption
alice = pyelliptic.ECC(curve='prime256v1')
bob = pyelliptic.ECC(curve='prime256v1')
bob_private_key = bob.get_privkey()
alice_public_key = alice.get_pubkey()
bob_public_key = bob.get_pubkey()
alice_private_key = alice.get_privkey()
print "Bob's private key: ", hexlify(bob_private_key)
print "Bob's public key: ", hexlify(bob_public_key)
print
print "Alices's private key: ", hexlify(alice_private_key)
print "Alices's public key: ", hexlify(alice_public_key)
print
print
print 'Initialize OnlyKey client...'
ok = OnlyKey()
print 'Done'
print
time.sleep(2)
ok.read_string(timeout_ms=100)
empty = 'a'
while not empty:
empty = ok.read_string(timeout_ms=100)
print 'You should see your OnlyKey blink 3 times'
print
print 'Setting ECC private...'
ok.set_ecc_key(101, (2+32), bob_private_key)
# Slot 101 - 132 for ECC
# Type 1 = Ed25519, Type 2 = p256r1, Type 3 = p256k1
# Key Features -
# if backup key = type + 128
# if signature key = type + 64
# if decryption key = type + 32
# if authentication key = type + 16
# For this example it will be a decryption key
time.sleep(1.5)
print ok.read_string()
time.sleep(2)
print 'You should see your OnlyKey blink 3 times'
print
payload = alice_public_key
#We are simulating message here, according to refernce below it is a known value to both parties - unsigned char message[256];
#
# // Reference - https://www.ietf.org/mail-archive/web/openpgp/current/msg00637.html
# // https://fossies.org/linux/misc/gnupg-2.1.17.tar.gz/gnupg-2.1.17/g10/ecdh.c
# // gcry_md_write(h, "\x00\x00\x00\x01", 4); /* counter = 1 */
# // gcry_md_write(h, secret_x, secret_x_size); /* x of the point X */
# // gcry_md_write(h, message, message_size); /* KDF parameters */
# // This is a limitation as we have to be able to fit the entire message to decrypt
# // In this way RSA seems to have an advantage?
# // /* Build kdf_params. */
# //{
# //IOBUF obuf;
# //
# //obuf = iobuf_temp();
# ///* variable-length field 1, curve name OID */
# //err = gpg_mpi_write_nohdr (obuf, pkey[0]);
# ///* fixed-length field 2 */
# //iobuf_put (obuf, PUBKEY_ALGO_ECDH);
# ///* variable-length field 3, KDF params */
# //err = (err ? err : gpg_mpi_write_nohdr (obuf, pkey[2]));
# ///* fixed-length field 4 */
# //iobuf_write (obuf, "Anonymous Sender ", 20);
# ///* fixed-length field 5, recipient fp */
# //iobuf_write (obuf, pk_fp, 20);
#
#
#
print 'Payload containing ephemeral public key', repr(payload)
print
# Compute the challenge pin
h = hashlib.sha256()
h.update(payload)
d = h.digest()
assert len(d) == 32
def get_button(byte):
ibyte = ord(byte)
if ibyte < 6:
return 1
return ibyte % 5 + 1
b1, b2, b3 = get_button(d[0]), get_button(d[15]), get_button(d[31])
print 'Sending the payload to the OnlyKey...'
ok.send_large_message2(msg=Message.OKDECRYPT, payload=payload, slot_id=101)
# Tim - The OnlyKey can send the code to enter but it would be better if the app generates
# the code, this way in order to trick a user into approving an unauthorized signature
# the app, in this case this python code would have to be hacked on the user's system.
# How the OnlyKey creates the three digit code:
# SHA256_CTX CRYPTO;
# sha256_init(&CRYPTO);
# sha256_update(&CRYPTO, large_buffer, large_data_offset); //step 1 create a sha256 hash of
# sha256_final(&CRYPTO, rsa_signature); //the data to sign
# if (rsa_signature[0] < 6) Challenge_button1 = '1'; //step 2 Convert first byte of hash to
# else { //first button to press (remainder of byte is a base 6 number 0 - 5)
# Challenge_button1 = rsa_signature[0] % 5;
# Challenge_button1 = Challenge_button1 + '0' + 1; //Add '0' and 1 so number will be ASCII 1 - 6
# }
# if (rsa_signature[15] < 6) Challenge_button2 = '1'; //step 3 do the same with 16th byte to
# else { // get Challenge_button2
# Challenge_button2 = rsa_signature[15] % 5;
# Challenge_button2 = Challenge_button2 + '0' + 1;
#}
# if (rsa_signature[31] < 6) Challenge_button3 = '1'; //step 4 do the same with 32nd byte to
# else { // get Challenge_button
# Challenge_button3 = rsa_signature[31] % 5;
# Challenge_button3 = Challenge_button3 + '0' + 1;
# }
# step 5 display the code to user to enter on OnlyKey
# This method prevents some malware on a users system from sending fake requests to be signed
# at the same time as real requests and tricking the user into signing the wrong data
print 'Please enter the 3 digit challenge code on OnlyKey (and press ENTER if necessary)'
print '{} {} {}'.format(b1, b2, b3)
raw_input()
shared_secret1 = alice.get_ecdh_key(bob.get_pubkey())
shared_secret2 = bob.get_ecdh_key(alice.get_pubkey())
print 'Trying to read the shared secret from OnlyKey...'
ok_shared_secret = ''
while ok_shared_secret == '':
time.sleep(0.5)
ok_shared_secret = ok.read_bytes(len(shared_secret1), to_str=True)
print 'OnlyKey Shared Secret =', hexlify(ok_shared_secret)
print 'Local Shared Secret1 =', hexlify(shared_secret1)
print
print 'Local Shared Secret2 =', hexlify(shared_secret2)
print
print 'Assert that both shared secrets match'
print(hexlify(alice.get_ecdh_key(bob.get_pubkey())))
assert repr(shared_secret1) == repr(ok_shared_secret)
print 'Ok, secrets match'
print
print 'Done'