aboutsummaryrefslogtreecommitdiff
path: root/test/functional/test_framework/crypto/bip324_cipher.py
blob: c9f0fa01512808cd351cf581dc7bcdea3f348245 (plain)
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
#!/usr/bin/env python3
# Copyright (c) 2022 The Bitcoin Core developers
# Distributed under the MIT software license, see the accompanying
# file COPYING or http://www.opensource.org/licenses/mit-license.php.

"""Test-only implementation of ChaCha20 Poly1305 AEAD Construction in RFC 8439 and FSChaCha20Poly1305 for BIP 324

It is designed for ease of understanding, not performance.

WARNING: This code is slow and trivially vulnerable to side channel attacks. Do not use for
anything but tests.
"""

import unittest

from .chacha20 import chacha20_block, REKEY_INTERVAL
from .poly1305 import Poly1305


def pad16(x):
    if len(x) % 16 == 0:
        return b''
    return b'\x00' * (16 - (len(x) % 16))


def aead_chacha20_poly1305_encrypt(key, nonce, aad, plaintext):
    """Encrypt a plaintext using ChaCha20Poly1305."""
    if plaintext is None:
        return None
    ret = bytearray()
    msg_len = len(plaintext)
    for i in range((msg_len + 63) // 64):
        now = min(64, msg_len - 64 * i)
        keystream = chacha20_block(key, nonce, i + 1)
        for j in range(now):
            ret.append(plaintext[j + 64 * i] ^ keystream[j])
    poly1305 = Poly1305(chacha20_block(key, nonce, 0)[:32])
    mac_data = aad + pad16(aad)
    mac_data += ret + pad16(ret)
    mac_data += len(aad).to_bytes(8, 'little') + msg_len.to_bytes(8, 'little')
    ret += poly1305.tag(mac_data)
    return bytes(ret)


def aead_chacha20_poly1305_decrypt(key, nonce, aad, ciphertext):
    """Decrypt a ChaCha20Poly1305 ciphertext."""
    if ciphertext is None or len(ciphertext) < 16:
        return None
    msg_len = len(ciphertext) - 16
    poly1305 = Poly1305(chacha20_block(key, nonce, 0)[:32])
    mac_data = aad + pad16(aad)
    mac_data += ciphertext[:-16] + pad16(ciphertext[:-16])
    mac_data += len(aad).to_bytes(8, 'little') + msg_len.to_bytes(8, 'little')
    if ciphertext[-16:] != poly1305.tag(mac_data):
        return None
    ret = bytearray()
    for i in range((msg_len + 63) // 64):
        now = min(64, msg_len - 64 * i)
        keystream = chacha20_block(key, nonce, i + 1)
        for j in range(now):
            ret.append(ciphertext[j + 64 * i] ^ keystream[j])
    return bytes(ret)


class FSChaCha20Poly1305:
    """Rekeying wrapper AEAD around ChaCha20Poly1305."""
    def __init__(self, initial_key):
        self._key = initial_key
        self._packet_counter = 0

    def _crypt(self, aad, text, is_decrypt):
        nonce = ((self._packet_counter % REKEY_INTERVAL).to_bytes(4, 'little') +
                 (self._packet_counter // REKEY_INTERVAL).to_bytes(8, 'little'))
        if is_decrypt:
            ret = aead_chacha20_poly1305_decrypt(self._key, nonce, aad, text)
        else:
            ret = aead_chacha20_poly1305_encrypt(self._key, nonce, aad, text)
        if (self._packet_counter + 1) % REKEY_INTERVAL == 0:
            rekey_nonce = b"\xFF\xFF\xFF\xFF" + nonce[4:]
            self._key = aead_chacha20_poly1305_encrypt(self._key, rekey_nonce, b"", b"\x00" * 32)[:32]
        self._packet_counter += 1
        return ret

    def decrypt(self, aad, ciphertext):
        return self._crypt(aad, ciphertext, True)

    def encrypt(self, aad, plaintext):
        return self._crypt(aad, plaintext, False)


# Test vectors from RFC8439 consisting of plaintext, aad, 32 byte key, 12 byte nonce and ciphertext
AEAD_TESTS = [
    # RFC 8439 Example from section 2.8.2
    ["4c616469657320616e642047656e746c656d656e206f662074686520636c6173"
     "73206f66202739393a204966204920636f756c64206f6666657220796f75206f"
     "6e6c79206f6e652074697020666f7220746865206675747572652c2073756e73"
     "637265656e20776f756c642062652069742e",
     "50515253c0c1c2c3c4c5c6c7",
     "808182838485868788898a8b8c8d8e8f909192939495969798999a9b9c9d9e9f",
     [7, 0x4746454443424140],
     "d31a8d34648e60db7b86afbc53ef7ec2a4aded51296e08fea9e2b5a736ee62d6"
     "3dbea45e8ca9671282fafb69da92728b1a71de0a9e060b2905d6a5b67ecd3b36"
     "92ddbd7f2d778b8c9803aee328091b58fab324e4fad675945585808b4831d7bc"
     "3ff4def08e4b7a9de576d26586cec64b61161ae10b594f09e26a7e902ecbd060"
     "0691"],
    # RFC 8439 Test vector A.5
    ["496e7465726e65742d4472616674732061726520647261667420646f63756d65"
     "6e74732076616c696420666f722061206d6178696d756d206f6620736978206d"
     "6f6e74687320616e64206d617920626520757064617465642c207265706c6163"
     "65642c206f72206f62736f6c65746564206279206f7468657220646f63756d65"
     "6e747320617420616e792074696d652e20497420697320696e617070726f7072"
     "6961746520746f2075736520496e7465726e65742d4472616674732061732072"
     "65666572656e6365206d6174657269616c206f7220746f206369746520746865"
     "6d206f74686572207468616e206173202fe2809c776f726b20696e2070726f67"
     "726573732e2fe2809d",
     "f33388860000000000004e91",
     "1c9240a5eb55d38af333888604f6b5f0473917c1402b80099dca5cbc207075c0",
     [0, 0x0807060504030201],
     "64a0861575861af460f062c79be643bd5e805cfd345cf389f108670ac76c8cb2"
     "4c6cfc18755d43eea09ee94e382d26b0bdb7b73c321b0100d4f03b7f355894cf"
     "332f830e710b97ce98c8a84abd0b948114ad176e008d33bd60f982b1ff37c855"
     "9797a06ef4f0ef61c186324e2b3506383606907b6a7c02b0f9f6157b53c867e4"
     "b9166c767b804d46a59b5216cde7a4e99040c5a40433225ee282a1b0a06c523e"
     "af4534d7f83fa1155b0047718cbc546a0d072b04b3564eea1b422273f548271a"
     "0bb2316053fa76991955ebd63159434ecebb4e466dae5a1073a6727627097a10"
     "49e617d91d361094fa68f0ff77987130305beaba2eda04df997b714d6c6f2c29"
     "a6ad5cb4022b02709beead9d67890cbb22392336fea1851f38"],
    # Test vectors exercising aad and plaintext which are multiples of 16 bytes.
    ["8d2d6a8befd9716fab35819eaac83b33269afb9f1a00fddf66095a6c0cd91951"
     "a6b7ad3db580be0674c3f0b55f618e34",
     "",
     "72ddc73f07101282bbbcf853b9012a9f9695fc5d36b303a97fd0845d0314e0c3",
     [0x3432b75f, 0xb3585537eb7f4024],
     "f760b8224fb2a317b1b07875092606131232a5b86ae142df5df1c846a7f6341a"
     "f2564483dd77f836be45e6230808ffe402a6f0a3e8be074b3d1f4ea8a7b09451"],
    ["",
     "36970d8a704c065de16250c18033de5a400520ac1b5842b24551e5823a3314f3"
     "946285171e04a81ebfbe3566e312e74ab80e94c7dd2ff4e10de0098a58d0f503",
     "77adda51d6730b9ad6c995658cbd49f581b2547e7c0c08fcc24ceec797461021",
     [0x1f90da88, 0x75dafa3ef84471a4],
     "aaae5bb81e8407c94b2ae86ae0c7efbe"],
]

FSAEAD_TESTS = [
    ["d6a4cb04ef0f7c09c1866ed29dc24d820e75b0491032a51b4c3366f9ca35c19e"
     "a3047ec6be9d45f9637b63e1cf9eb4c2523a5aab7b851ebeba87199db0e839cf"
     "0d5c25e50168306377aedbe9089fd2463ded88b83211cf51b73b150608cc7a60"
     "0d0f11b9a742948482e1b109d8faf15b450aa7322e892fa2208c6691e3fecf4c"
     "711191b14d75a72147",
     "786cb9b6ebf44288974cf0",
     "5c9e1c3951a74fba66708bf9d2c217571684556b6a6a3573bff2847d38612654",
     500,
     "9dcebbd3281ea3dd8e9a1ef7d55a97abd6743e56ebc0c190cb2c4e14160b385e"
     "0bf508dddf754bd02c7c208447c131ce23e47a4a14dfaf5dd8bc601323950f75"
     "4e05d46e9232f83fc5120fbbef6f5347a826ec79a93820718d4ec7a2b7cfaaa4"
     "4b21e16d726448b62f803811aff4f6d827ed78e738ce8a507b81a8ae13131192"
     "8039213de18a5120dc9b7370baca878f50ff254418de3da50c"],
    ["8349b7a2690b63d01204800c288ff1138a1d473c832c90ea8b3fc102d0bb3adc"
     "44261b247c7c3d6760bfbe979d061c305f46d94c0582ac3099f0bf249f8cb234",
     "",
     "3bd2093fcbcb0d034d8c569583c5425c1a53171ea299f8cc3bbf9ae3530adfce",
     60000,
     "30a6757ff8439b975363f166a0fa0e36722ab35936abd704297948f45083f4d4"
     "99433137ce931f7fca28a0acd3bc30f57b550acbc21cbd45bbef0739d9caf30c"
     "14b94829deb27f0b1923a2af704ae5d6"],
]


class TestFrameworkAEAD(unittest.TestCase):
    def test_aead(self):
        """ChaCha20Poly1305 AEAD test vectors."""
        for test_vector in AEAD_TESTS:
            hex_plain, hex_aad, hex_key, hex_nonce, hex_cipher = test_vector
            plain = bytes.fromhex(hex_plain)
            aad = bytes.fromhex(hex_aad)
            key = bytes.fromhex(hex_key)
            nonce = hex_nonce[0].to_bytes(4, 'little') + hex_nonce[1].to_bytes(8, 'little')

            ciphertext = aead_chacha20_poly1305_encrypt(key, nonce, aad, plain)
            self.assertEqual(hex_cipher, ciphertext.hex())
            plaintext = aead_chacha20_poly1305_decrypt(key, nonce, aad, ciphertext)
            self.assertEqual(plain, plaintext)

    def test_fschacha20poly1305aead(self):
        "FSChaCha20Poly1305 AEAD test vectors."
        for test_vector in FSAEAD_TESTS:
            hex_plain, hex_aad, hex_key, msg_idx, hex_cipher = test_vector
            plain = bytes.fromhex(hex_plain)
            aad = bytes.fromhex(hex_aad)
            key = bytes.fromhex(hex_key)

            enc_aead = FSChaCha20Poly1305(key)
            dec_aead = FSChaCha20Poly1305(key)

            for _ in range(msg_idx):
                enc_aead.encrypt(b"", None)
            ciphertext = enc_aead.encrypt(aad, plain)
            self.assertEqual(hex_cipher, ciphertext.hex())

            for _ in range(msg_idx):
                dec_aead.decrypt(b"", None)
            plaintext = dec_aead.decrypt(aad, ciphertext)
            self.assertEqual(plain, plaintext)