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trezor-firmware/core/tests/test_trezor.crypto.cosi.py

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from common import * # isort:skip
from trezor.crypto import cosi, random
from trezor.crypto.curve import ed25519
class TestCryptoEd25519Cosi(unittest.TestCase):
def random_signers(self, N: int) -> tuple[list[bytes], list[bytes]]:
keys = []
pubkeys = []
for j in range(N):
keys.append(ed25519.generate_secret())
pubkeys.append(ed25519.publickey(keys[j]))
return keys, pubkeys
def cosign(
self, message: bytes, keys: list[bytes], pubkeys: list[bytes]
) -> tuple[bytes, bytes]:
# phase 0: combine pubkeys
pubkey = cosi.combine_publickeys(pubkeys)
# phase 1: create nonces, commitments (R values) and combine commitments
nonces = []
Rs = []
for _ in range(len(keys)):
nonce, R = cosi.commit()
nonces.append(nonce)
Rs.append(R)
R = ed25519.cosi_combine_publickeys(Rs)
# phase 2: sign and combine signatures
sigs = []
for key, nonce in zip(keys, nonces):
sigs.append(cosi.sign(key, message, nonce, R, pubkey))
return pubkey, cosi.combine_signatures(R, sigs)
def test_cosi(self):
for N in range(1, 11):
# generate random inputs
msg = random.bytes(128)
keys, pubkeys = self.random_signers(N)
# generate combined signature
pubkey, sig = self.cosign(msg, keys, pubkeys)
# check signature using normal ed25519.verify
res = ed25519.verify(pubkey, sig, msg)
self.assertTrue(res)
def test_select_keys(self):
keys, pubkeys = self.random_signers(5)
# try all possible combinations of signers = all 5-bit sigmasks
for sigmask in range(1, 32):
selected_keys = cosi.select_keys(sigmask, keys)
selected_pubkeys = cosi.select_keys(sigmask, pubkeys)
# check that the selection picks the right key combinations
for key, pubkey in zip(selected_keys, selected_pubkeys):
self.assertEqual(ed25519.publickey(key), pubkey)
# count number of ones
count = 0
for i in range(5):
if sigmask & (1 << i):
count += 1
self.assertEqual(len(selected_keys), count)
self.assertEqual(len(selected_pubkeys), count)
def test_verify(self):
keys, all_pubkeys = self.random_signers(5)
# try all possible combinations of signers = all 5-bit sigmasks
for sigmask in range(1, 32):
message = random.bytes(128)
selected_keys = cosi.select_keys(sigmask, keys)
selected_pubkeys = cosi.select_keys(sigmask, all_pubkeys)
_, sig = self.cosign(message, selected_keys, selected_pubkeys)
res = cosi.verify(sig, message, len(selected_keys), all_pubkeys, sigmask)
self.assertTrue(res)
res = cosi.verify(sig, message, 1, all_pubkeys, sigmask)
self.assertTrue(res)
res = cosi.verify(
sig, message, len(selected_keys) + 1, all_pubkeys, sigmask
)
self.assertFalse(res)
if __name__ == "__main__":
unittest.main()