def test_threshold_instance(T, N):
commitments = []
# fragments[i][j] = fragment held by player i,
# received from player j
fragments = [[None] * N for _ in range(N)]
secrets = []
# Step 1 : Threshold.create
for player in range(N):
secret_key, commi, frags = Threshold.create(T, N)
for target, frag in enumerate(frags):
fragments[target][player] = frag
commitments.append(commi)
secrets.append(secret_key)
# Step 2 : Threshold.verify_secret_fragment
for player_source in range(1, N + 1):
for player_target in range(1, N + 1):
assert Threshold.verify_secret_fragment(
player_target, fragments[player_target - 1][player_source - 1],
commitments[player_source - 1], T)
# Step 3 : master_pubkey = PublicKey.aggregate_insecure(...)
# secret_share = PrivateKey.aggregate_insecure(...)
master_pubkey = PublicKey.aggregate_insecure(
[commitments[i][0] for i in range(N)])
secret_shares = [
PrivateKey.aggregate_insecure(fragment_row)
for fragment_row in fragments
]
master_privkey = PrivateKey.aggregate_insecure(secrets)
msg = ("Test").encode("utf-8")
signature_actual = master_privkey.sign_insecure(msg)
# Step 4 : sig_share = Threshold.sign_with_coefficient(...)
# Check every combination of T players
for X in combinations(range(1, N + 1), T):
# X: a list of T indices like [1, 2, 5]
# Check signatures
signature_shares = [
Threshold.sign_with_coefficient(secret_shares[x - 1], msg, x, X)
for x in X
]
signature_cand = InsecureSignature.aggregate(signature_shares)
assert signature_cand == signature_actual
# Check that the signature actually verifies the message
assert signature_actual.verify([Util.hash256(msg)], [master_pubkey])
# Step 4b : Alternatively, we can add the lagrange coefficients
# to 'unit' signatures.
for X in combinations(range(1, N + 1), T):
# X: a list of T indices like [1, 2, 5]
# Check signatures
signature_shares = [secret_shares[x - 1].sign_insecure(msg) for x in X]
signature_cand = Threshold.aggregate_unit_sigs(signature_shares, X)
assert signature_cand == signature_actual
def aggregate_signatures(signatures: Sequence[BLSSignature]) -> BLSSignature:
if len(signatures) == 0:
return EMPTY_SIGNATURE
signatures_chia = [
InsecureSignature.from_bytes(signature) for signature in signatures
]
aggregated_signature = InsecureSignature.aggregate(signatures_chia)
aggregated_signature_bytes = aggregated_signature.serialize()
return cast(BLSSignature, aggregated_signature_bytes)