def check_proof_multi(commitment, proof, x, ys, setup):
"""
Check a proof for a Kate commitment for an evaluation f(x w^i) = y_i
"""
n = len(ys)
root_of_unity = get_root_of_unity(n)
# Interpolate at a coset. Note because it is a coset, not the subgroup, we have to multiply the
# polynomial coefficients by x^i
interpolation_polynomial = fft(ys, MODULUS, root_of_unity, True)
interpolation_polynomial = [div(c, pow(x, i, MODULUS)) for i, c in enumerate(interpolation_polynomial)]
# Verify the pairing equation
#
# e([commitment - interpolation_polynomial(s)], [1]) = e([proof], [s^n - x^n])
# equivalent to
# e([commitment - interpolation_polynomial]^(-1), [1]) * e([proof], [s^n - x^n]) = 1_T
#
xn_minus_yn = b.add(setup[1][n], b.multiply(b.neg(b.G2), pow(x, n, MODULUS)))
commitment_minus_interpolation = b.add(commitment, b.neg(lincomb(
setup[0][:len(interpolation_polynomial)], interpolation_polynomial, b.add, b.Z1)))
pairing_check = b.pairing(b.G2, b.neg(commitment_minus_interpolation), False)
pairing_check *= b.pairing(xn_minus_yn, proof, False)
pairing = b.final_exponentiate(pairing_check)
return pairing == b.FQ12.one()
def verify(points, commitment, proof):
# Crop the base points to just what we need
points = points[:2**len(proof.L)]
# Fiat-shamir randomness value
r = hash(serialize_point(commitment))
# For verification, we need to generate the same random linear combination of
# base points that the prover did.. But because we don't need to use it until
# the end, we do it more efficiently here: when we progress through the rounds,
# we keep track of how many times each points[i] will appear in the final
# result...
points_coeffs = [1]
# log(n) rounds, just like the prover...
for i in range(len(proof.L)):
r = hash(r + serialize_point(proof.L[i]) + serialize_point(proof.R[i]))
# Generate random coefficient for recombining (same as the prover)
a = int.from_bytes(r, 'little') % b.curve_order
# print('a value: ', a)
# Add L and R into the commitment, applying the appropriate coefficients
commitment = b.add(
proof.L[i],
b.add(b.multiply(commitment, a), b.multiply(proof.R[i], a**2)))
# print('intermediate commitment:', commitment)
# Update the coefficients (points_coeffs[i] = how many times points[i] will
# appear in the single base point of the last round)
points_coeffs = sum([[(x * a) % b.curve_order, x]
for x in points_coeffs], [])
# Finally, we do the linear combination
combined_point = lincomb(points, points_coeffs, b.add, b.Z1)
# Base case check: base_point * coefficient ?= commitment
return b.eq(b.multiply(combined_point, proof.tip), commitment)
def checker(data, msg):
agg_pk = Z1
agg_sig = Z2
for i in range(len(data)):
if data[i]["Vote"].encode() == msg:
agg_pk = add(agg_pk, pubkey_to_G1(bytes.fromhex(data[i]["PK"])))
agg_sig = add(agg_sig,
signature_to_G2(bytes.fromhex(data[i]["Sign"])))
isok = singlechecker(agg_pk, agg_sig, msg)
print(isok)
def prove_evaluation(points, commitment, poly, x, y):
assert is_power_of_two(len(poly))
# Crop the base points to just what we need. We add an additional base point,
# which we will use to mix in the _evaluation_ of the polynomial.
points, H = points[:len(poly)], points[len(poly)]
# Alongside the base points, we track the powers of the x coordinate we are
# proving an evaluation for. These points get manipulated in the same way as the
# base points do.
xpowers = [pow(x, i, b.curve_order) for i in range(len(poly))]
# Left-side points for the proof
L = []
# Right-side points for the proof
R = []
# Fiat-shamir randomness value
r = hash(
serialize_point(commitment) + x.to_bytes(32, 'little') +
y.to_bytes(32, 'little'))
# For security, we randomize H
H = b.multiply(H, int.from_bytes(r, 'little') % b.curve_order)
while len(poly) > 1:
# Generate the left-side and right-side points, except we also mix in a similarly
# constructed "commitment" that uses `H * powers of x` as its base instead of the
# base points.
polyL, polyR = left_half(poly), right_half(poly)
pointsL, pointsR = left_half(points), right_half(points)
xpowersL, xpowersR = left_half(xpowers), right_half(xpowers)
yL = commit(pointsR, polyL)
yR = commit(pointsL, polyR)
L.append(
b.add(yL, b.multiply(H,
sum(a * b for a, b in zip(xpowersR, polyL)))))
R.append(
b.add(yR, b.multiply(H,
sum(a * b for a, b in zip(xpowersL, polyR)))))
# Generate random coefficient for recombining the L and R and commitment
r = hash(r + serialize_point(L[-1]) + serialize_point(R[-1]))
a = int.from_bytes(r, 'little') % b.curve_order
# print('a value: ', a)
# Generate half-size polynomial and points for the next round. Notice how we treat
# the powers of x the same way that we do the base points
poly = [(cL + cR * a) % b.curve_order
for (cL, cR) in zip(polyL, polyR)]
points = [
b.add(b.multiply(pL, a), pR) for (pL, pR) in zip(pointsL, pointsR)
]
xpowers = [(xL * a + xR) % b.curve_order
for (xL, xR) in zip(xpowersL, xpowersR)]
# print('intermediate commitment:', b.add(commit(points, poly), b.multiply(H, sum(a*b for a,b in zip(xpowers, poly)))))
return Proof(L, R, poly[0])
def execute(cls, stack: MichelsonStack, stdout: List[str],
context: AbstractContext):
a, b = cast(
Tuple[Union[IntType, NatType, MutezType, TimestampType,
BLS12_381_G1Type, BLS12_381_G2Type, BLS12_381_FrType],
...], stack.pop2())
res_type, = dispatch_types(
type(a),
type(b),
mapping={
(NatType, NatType): (NatType, ),
(NatType, IntType): (IntType, ),
(IntType, NatType): (IntType, ),
(IntType, IntType): (IntType, ),
(TimestampType, IntType): (TimestampType, ),
(IntType, TimestampType): (TimestampType, ),
(MutezType, MutezType): (MutezType, ),
(BLS12_381_FrType, BLS12_381_FrType): (BLS12_381_FrType, ),
(BLS12_381_G1Type, BLS12_381_G1Type): (BLS12_381_G1Type, ),
(BLS12_381_G2Type, BLS12_381_G2Type): (BLS12_381_G2Type, )
})
res_type = cast(
Union[Type[IntType], Type[NatType], Type[TimestampType],
Type[MutezType], Type[BLS12_381_G1Type],
Type[BLS12_381_G2Type], Type[BLS12_381_FrType]], res_type)
if issubclass(res_type, IntType):
res = res_type.from_value(int(a) + int(b)) # type: ignore
else:
res = res_type.from_point(bls12_381.add(
a.to_point(), b.to_point())) # type: ignore
stack.push(res)
stdout.append(format_stdout(cls.prim, [a, b], [res])) # type: ignore
return cls(stack_items_added=1)
def _AggregatePKs(PKs: Sequence[BLSPubkey]) -> BLSPubkey:
assert len(PKs) >= 1, 'Insufficient number of PKs. (n < 1)'
aggregate = Z1 # Seed with the point at infinity
for pk in PKs:
pubkey_point = pubkey_to_G1(pk)
aggregate = add(aggregate, pubkey_point)
return G1_to_pubkey(aggregate)
def prove(points, commitment, poly):
assert is_power_of_two(len(poly))
# Crop the base points to just what we need
points = points[:len(poly)]
# Left-side points for the proof
L = []
# Right-side points for the proof
R = []
# Fiat-shamir randomness value
r = hash(serialize_point(commitment))
# log(n) rounds...
while len(poly) > 1:
# Generate the left-side and right-side points
polyL, polyR = left_half(poly), right_half(poly)
pointsL, pointsR = left_half(points), right_half(points)
yL = commit(pointsR, polyL)
yR = commit(pointsL, polyR)
L.append(yL)
R.append(yR)
# Generate random coefficient for recombining the L and R and commitment
r = hash(r + serialize_point(yL) + serialize_point(yR))
a = int.from_bytes(r, 'little') % b.curve_order
# print('a value: ', a)
# Generate half-size polynomial and points for the next round
poly = [(cL + cR * a) % b.curve_order
for (cL, cR) in zip(polyL, polyR)]
points = [
b.add(b.multiply(pL, a), pR) for (pL, pR) in zip(pointsL, pointsR)
]
# print('intermediate commitment:', commit(points, poly))
return Proof(L, R, poly[0])
def verify_multiple(pubkeys: Sequence[BLSPubkey], messages: Sequence[bytes],
signature: BLSSignature, domain: int) -> bool:
len_msgs = len(messages)
if len(pubkeys) != len_msgs:
raise ValidationError(
"len(pubkeys) (%s) should be equal to len(messages) (%s)" %
(len(pubkeys), len_msgs))
try:
o = FQ12([1] + [0] * 11)
for m_pubs in set(messages):
# aggregate the pubs
group_pub = Z1
for i in range(len_msgs):
if messages[i] == m_pubs:
group_pub = add(group_pub, decompress_G1(pubkeys[i]))
o *= pairing(hash_to_G2(m_pubs, domain),
group_pub,
final_exponentiate=False)
o *= pairing(decompress_G2(signature),
neg(G1),
final_exponentiate=False)
final_exponentiation = final_exponentiate(o)
return final_exponentiation == FQ12.one()
except (ValidationError, ValueError, AssertionError):
return False
def generate_proof(data_tree, commitment_tree, proof_tree, indices, setup):
committee_root = commitment_tree[0][0]
# Generate a random r value; we use a power of r as a coefficient for each sub-leaf
# to create a random linear combination
r = int.from_bytes(
hash(str([committee_root[0].n] + indices).encode('utf-8')),
'big') % b.curve_order
#print("r", r)
# Total polynomial that we are evaluating
total_poly_evaluations = [0] * WIDTH
# The set of all intermediate commitments
commitments = []
total_proofs = b.Z1
for i, index in enumerate(indices):
c = []
# Walk from top to bottom of the tree
for d in range(DEPTH):
# Power of r for this leaf
rfactor = pow(r, i * DEPTH + d, MODULUS)
# Position of the index in this layer of data
position_of_leaf = index // WIDTH**(DEPTH - d - 1)
# Position of the index within its data chunk
sub_index = position_of_leaf % WIDTH
proof = proof_tree[d][position_of_leaf]
# Add in rfactor*D / (X - w**i) to the total
total_proofs = b.add(total_proofs, b.multiply(proof, rfactor))
# Provide as part of the proof all intermediate-level commitments
if d > 0:
c.append(commitment_tree[d][position_of_leaf // WIDTH])
commitments.append(c)
# Generate a polynomial commitment for the result
return commitments, b.normalize(total_proofs)
def _interpolate_in_group(group_shares:Dict[int,tuple], group_gen:tuple) -> tuple:
lagrange_coeff = _all_lagrange_coeff_at_point(0, group_shares.keys(), bls_curve.curve_order)
combined_group_element = bls_curve.multiply(group_gen, 0)
for id, gr_el in group_shares.items():
combined_group_element = bls_curve.add(combined_group_element, bls_curve.multiply(group_shares[id], lagrange_coeff[id]))
return combined_group_element
def _fft(vals, modulus, roots_of_unity):
if len(vals) <= 4 and type(vals[0]) != tuple:
#return vals
return _simple_ft(vals, modulus, roots_of_unity)
elif len(vals) == 1 and type(vals[0]) == tuple:
return vals
L = _fft(vals[::2], modulus, roots_of_unity[::2])
R = _fft(vals[1::2], modulus, roots_of_unity[::2])
o = [0 for i in vals]
for i, (x, y) in enumerate(zip(L, R)):
y_times_root = b.multiply(
y,
roots_of_unity[i]) if type(y) == tuple else y * roots_of_unity[i]
o[i] = b.add(
x,
y_times_root) if type(x) == tuple else (x + y_times_root) % modulus
o[i + len(L)] = b.add(x, b.neg(y_times_root)) if type(
x) == tuple else (x - y_times_root) % modulus
return o
def Aggregate(signatures: Sequence[BLSSignature]) -> BLSSignature:
if len(signatures) < 1:
raise ValidationError(
'Insufficient number of signatures: should be greater than'
' or equal to 1, got %d' % len(signatures))
aggregate = Z2 # Seed with the point at infinity
for signature in signatures:
signature_point = signature_to_G2(signature)
aggregate = add(aggregate, signature_point)
return G2_to_signature(aggregate)
def check_proof_single(commitment, proof, x, y, setup):
"""
Check a proof for a Kate commitment for an evaluation f(x) = y
"""
# Verify the pairing equation
#
# e([commitment - y], [1]) = e([proof], [s - x])
# equivalent to
# e([commitment - y]^(-1), [1]) * e([proof], [s - x]) = 1_T
#
s_minus_x = b.add(setup[1][1], b.multiply(b.neg(b.G2), x))
commitment_minus_y = b.add(commitment, b.multiply(b.neg(b.G1), y))
pairing_check = b.pairing(b.G2, b.neg(commitment_minus_y), False)
pairing_check *= b.pairing(s_minus_x, proof, False)
pairing = b.final_exponentiate(pairing_check)
return pairing == b.FQ12.one()
def verify_evaluation(points, commitment, proof, x, y):
# Crop the base points to just what we need. We add an additional base point,
# which we will use to mix in the _evaluation_ of the polynomial.
points, H = points[:2**len(proof.L)], points[2**len(proof.L)]
# Powers of x, as in the prover
xpowers = [pow(x, i, b.curve_order) for i in range(len(poly))]
# Fiat-shamir randomness value
r = hash(
serialize_point(commitment) + x.to_bytes(32, 'little') +
y.to_bytes(32, 'little'))
# For security, we randomize H
H = b.multiply(H, int.from_bytes(r, 'little') % b.curve_order)
# We "mix in" H * the claimed evaluation P(x) = y. Notice that `H * P(x)` equals the
# dot-product of `H * powers of x` and the polynomial coefficients, so it has the
# "same format" as the polynomial commitment itself. This allows us to verify the
# evaluation using the same technique that we use to just prove that the commitment
# is valid
commitment = b.add(commitment, b.multiply(H, y))
# Track the linear combination so we can generate the final-round point and xpower,
# just as before
points_coeffs = [1]
for i in range(len(proof.L)):
# Generate random coefficient for recombining (same as the prover)
r = hash(r + serialize_point(proof.L[i]) + serialize_point(proof.R[i]))
a = int.from_bytes(r, 'little') % b.curve_order
# print('a value: ', a)
# Add L and R into the commitment, applying the appropriate coefficients
commitment = b.add(
proof.L[i],
b.add(b.multiply(commitment, a), b.multiply(proof.R[i], a**2)))
# print('intermediate commitment:', commitment)
# Update the coefficients (as in basic verification above)
points_coeffs = sum([[(x * a) % b.curve_order, x]
for x in points_coeffs], [])
# Finally, we do the linear combination; same one for base points and x powers
combined_point = lincomb(points, points_coeffs, b.add, b.Z1)
combined_x_powers = sum(p * c for p, c in zip(xpowers, points_coeffs))
# Base case check: base_point * coefficient ?= commitment. Note that here we
# have to also mix H * the combined xpower into the final base point
return b.eq(
b.add(b.multiply(combined_point, proof.tip),
b.multiply(H, (proof.tip * combined_x_powers) % b.curve_order)),
commitment)
def get_aggregate_key(keys):
r = b.Z1
for i, key in keys.items():
key_point = pubkey_to_G1(key)
coef = 1
for j in keys:
if j != i:
coef = -coef * (j + 1) * prime_field_inv(
i - j, b.curve_order) % b.curve_order
r = b.add(r, b.multiply(key_point, coef))
return G1_to_pubkey(r)
def reconstruct(signatures):
r = b.Z2
for i, sig in signatures.items():
sig_point = signature_to_G2(sig)
coef = 1
for j in signatures:
if j != i:
coef = -coef * (j + 1) * prime_field_inv(
i - j, b.curve_order) % b.curve_order
r = b.add(r, b.multiply(sig_point, coef))
return G2_to_signature(r)
def _simple_ft(vals, modulus, roots_of_unity):
L = len(roots_of_unity)
o = []
for i in range(L):
last = b.Z1 if type(vals[0]) == tuple else 0
for j in range(L):
if type(vals[0]) == tuple:
last = b.add(last,
b.multiply(vals[j], roots_of_unity[(i * j) % L]))
else:
last += vals[j] * roots_of_unity[(i * j) % L]
o.append(last if type(last) == tuple else last % modulus)
return o
def verify_proof(proof, commitment_root, indices, values, setup):
# Regenerate the same r value as above
r = int.from_bytes(
hash(str([commitment_root[0].n] + indices).encode('utf-8')),
'big') % b.curve_order
#print("r", r)
commitments, witness = proof
# We're making a big pairing check that essentially checks the equation:
# sum [(P_i - y_i) * r_i * Z(everything except x_i)] = w * Z(everything) = sum [Q_i * r_i * Z(everything)]
# where Z(set) = product: (X - s) for s in set
pairing_check = b.FQ12.one()
for i, (c, index, v) in enumerate(zip(commitments, indices, values)):
for d in range(DEPTH):
rfactor = pow(r, i * DEPTH + d, MODULUS)
position_of_leaf = index // WIDTH**(DEPTH - d - 1)
# Position of this leaf in the data
sub_index = position_of_leaf % WIDTH
#print('d', d, 'i', index, 'rfactor', rfactor, 'pos', position_of_leaf)
# P_i
comm = c[d - 1] if d else commitment_root
comm = (comm[0], comm[1], b.FQ.one())
leaf = hash_point_to_field(c[d]) if d < DEPTH - 1 else v
#print('comm', comm, 'subindex', sub_index, 'leaf', leaf)
# (P_i - y_i) * r_i
comm_minus_leaf_times_r = b.multiply(
b.add(comm, b.multiply(b.G1, MODULUS - leaf)), rfactor)
# Z(everything except x_i)
Z_comm = b.multiply(setup[3][sub_index],
field.inv(LAGRANGE_POLYS[sub_index][-1]))
# Add the product into the pairing
pairing_check *= b.pairing(Z_comm, comm_minus_leaf_times_r, False)
# Z(everything)
global_Z_comm = b.add(setup[1][WIDTH], b.neg(setup[1][0]))
# Subtract out sum [Q_i * r_i * Z(everything)]
pairing_check *= b.pairing(b.neg(global_Z_comm),
(witness[0], witness[1], b.FQ.one()), False)
o = b.final_exponentiate(pairing_check)
assert o == b.FQ12.one(), o
return o == b.FQ12.one()
def _AggregatePKs(PKs: Sequence[BLSPubkey]) -> BLSPubkey:
"""
Aggregate the public keys.
Raise `ValidationError` when there is input validation error.
"""
try:
assert len(PKs) >= 1, 'Insufficient number of PKs. (n < 1)'
except Exception as e:
raise ValidationError(e)
aggregate = Z1 # Seed with the point at infinity
for pk in PKs:
pubkey_point = pubkey_to_G1(pk)
aggregate = add(aggregate, pubkey_point)
return G1_to_pubkey(aggregate)
def hash_to_G2(message: bytes, DST: bytes) -> G2Uncompressed:
"""
Convert a message to a point on G2 as defined here:
https://tools.ietf.org/html/draft-irtf-cfrg-hash-to-curve-05#section-3
Contants and inputs follow the ciphersuite ``BLS12381G2-SHA256-SSWU-RO-`` defined here:
https://tools.ietf.org/html/draft-irtf-cfrg-hash-to-curve-05#section-8.9.2
"""
u0 = hash_to_base_FQ2(message, 0, DST)
u1 = hash_to_base_FQ2(message, 1, DST)
q0 = map_to_curve_G2(u0)
q1 = map_to_curve_G2(u1)
r = add(q0, q1)
p = clear_cofactor_G2(r)
return p
def hash_to_G2(message: bytes, DST: bytes,
hash_function: HASH) -> G2Uncompressed:
"""
Convert a message to a point on G2 as defined here:
https://tools.ietf.org/html/draft-irtf-cfrg-hash-to-curve-07#section-6.6.3
The idea is to first hash into FQ2 and then use SSWU to map the result into G2.
Contants and inputs follow the ciphersuite ``BLS12381G2_XMD:SHA-256_SSWU_RO_`` defined here:
https://tools.ietf.org/html/draft-irtf-cfrg-hash-to-curve-07#section-8.8.2
"""
u0, u1 = hash_to_field_FQ2(message, 2, DST, hash_function)
q0 = map_to_curve_G2(u0)
q1 = map_to_curve_G2(u1)
r = add(q0, q1)
p = clear_cofactor_G2(r)
return p
def derive_public_child(master_pubkey_share: bytes,
path: bytes,
master_pubkey: bytes = None) -> tuple:
if not master_pubkey:
master_pubkey = master_pubkey_share
root_public_key, root_public_chaincode = parse_master_pubkey(master_pubkey)
root_pubkey_address = bls_conv.G1_to_pubkey(root_public_key)
public_chaincode_address = bls_conv.G1_to_pubkey(root_public_chaincode)
h = _hash_to_bls_field(
_derivation_format_hash_input(root_pubkey_address,
public_chaincode_address, path))
public_key_share, public_chaincode_share = parse_master_pubkey(
master_pubkey_share)
return bls_curve.add(public_key_share,
bls_curve.multiply(public_chaincode_share, h))
def fk20_multi_data_availability_optimized(polynomial, l, setup):
"""
FK20 multi-proof method, optimized for dava availability where the top half of polynomial
coefficients == 0
"""
assert is_power_of_two(len(polynomial))
n = len(polynomial) // 2
k = n // l
assert is_power_of_two(n)
assert is_power_of_two(l)
assert k >= 1
assert all(x == 0 for x in polynomial[n:])
reduced_polynomial = polynomial[:n]
# Preprocessing part -- this is independent from the polynomial coefficients and can be
# done before the polynomial is known, it only needs to be computed once
xext_fft = []
for i in range(l):
x = setup[0][n - l - 1 - i::-l] + [b.Z1]
xext_fft.append(toeplitz_part1(x))
add_instrumentation()
hext_fft = [b.Z1] * 2 * k
for i in range(l):
toeplitz_coefficients = reduced_polynomial[- i - 1::l] + [0] * (k + 1) \
+ reduced_polynomial[2 * l - i - 1: - l - i:l]
# Compute the vector h from the paper using a Toeplitz matric multiplication
hext_fft = [
b.add(v, w) for v, w in zip(
hext_fft, toeplitz_part2(toeplitz_coefficients, xext_fft[i]))
]
# Final FFT done after summing all h vectors
h = toeplitz_part3(hext_fft)
h = h + [b.Z1] * k
# The proofs are the DFT of the h vector
return fft(h, MODULUS, get_root_of_unity(2 * k))
def Aggregate(cls, signatures: Sequence[BLSSignature]) -> BLSSignature:
"""
The Aggregate algorithm aggregates multiple signatures into one.
Raise `ValidationError` when there is input validation error.
"""
try:
# Inputs validation
for signature in signatures:
assert cls._is_valid_signature(signature)
# Preconditions
assert len(signatures) >= 1
except Exception as e:
raise ValidationError(e)
# Procedure
aggregate = Z2 # Seed with the point at infinity
for signature in signatures:
signature_point = signature_to_G2(signature)
aggregate = add(aggregate, signature_point)
return G2_to_signature(aggregate)
def fk20_multi(polynomial, l, setup):
"""
For a polynomial of size n, let w be a n-th root of unity. Then this method will return
k=n/l KZG proofs for the points
proof[0]: w^(0*l + 0), w^(0*l + 1), ... w^(0*l + l - 1)
proof[0]: w^(0*l + 0), w^(0*l + 1), ... w^(0*l + l - 1)
...
proof[i]: w^(i*l + 0), w^(i*l + 1), ... w^(i*l + l - 1)
...
"""
n = len(polynomial)
k = n // l
assert is_power_of_two(n)
assert is_power_of_two(l)
assert k >= 1
# Preprocessing part -- this is independent from the polynomial coefficients and can be
# done before the polynomial is known, it only needs to be computed once
xext_fft = []
for i in range(l):
x = setup[0][n - l - 1 - i::-l] + [b.Z1]
xext_fft.append(toeplitz_part1(x))
hext_fft = [b.Z1] * 2 * k
for i in range(l):
toeplitz_coefficients = polynomial[-i - 1::l] + [0] * (
k + 1) + polynomial[2 * l - i - 1:-l - i:l]
# Compute the vector h from the paper using a Toeplitz matric multiplication
hext_fft = [
b.add(v, w) for v, w in zip(
hext_fft, toeplitz_part2(toeplitz_coefficients, xext_fft[i]))
]
h = toeplitz_part3(hext_fft)
# The proofs are the DFT of the h vector
return fft(h, MODULUS, get_root_of_unity(k))
def aggregate_pubkeys(pubkeys: Sequence[BLSPubkey]) -> BLSPubkey:
o = Z1
for p in pubkeys:
o = add(o, decompress_G1(p))
return BLSPubkey(compress_G1(o))
def aggregate_signatures(signatures: Sequence[BLSSignature]) -> BLSSignature:
o = Z2
for s in signatures:
o = FQP_point_to_FQ2_point(add(o, decompress_G2(s)))
return BLSSignature(compress_G2(o))
def aggregate_pubkeys(pubkeys: Sequence[int]) -> int:
o = Z1
for p in pubkeys:
o = add(o, decompress_G1(p))
return compress_G1(o)
def aggregate_signatures(signatures: Sequence[bytes]) -> Tuple[int, int]:
o = Z2
for s in signatures:
o = FQP_point_to_FQ2_point(add(o, decompress_G2(s)))
return compress_G2(o)
m1, m2 = [int(sha256(i).hexdigest(), 16) for i in [b"D", b"R"]]
idx, ny = [(i, j) for i, j in enumerate(result) if j["Name"] == 'New York'][0]
ny["Sign"] = G2_to_signature(
multiply(multiply(signature_to_G2(unhex(ny["Sign"])), invert(m1, order)),
m2)).hex()
ny["Vote"] = "R"
assert bls.Verify(unhex(ny["PK"]), ny["Vote"].encode(), unhex(ny["Sign"]))
result[idx] = ny
xored_flag = unhex(connect(result).decode())
fake_result = result[:]
w = fake_result[idx + 1]
ny = fake_result[idx]
ny["Sign"] = G2_to_signature(
add(signature_to_G2(unhex(ny["Sign"])),
multiply(signature_to_G2(unhex(w["Sign"])), 2))).hex()
w["Sign"] = G2_to_signature(neg(signature_to_G2(unhex(w["Sign"])))).hex()
assert bls.Verify(bls._AggregatePKs([unhex(ny["PK"]),
unhex(w["PK"])]), b'R',
bls.Aggregate([unhex(ny["Sign"]),
unhex(w["Sign"])]))
fake_result[idx] = ny
fake_result[idx + 1] = w
fake_flag = connect(fake_result)
flag = bytexor(fake_flag, xored_flag)
print(flag)
assert flag == b'inctf{BLS_574nd5_f0r_B0n3h_Lynn_Sh4ch4m}'
