def verify(proofs,N):
# determine the length of the longest proof
max_MN = 2**max([len(proof.L) for proof in proofs])
# curve points
Z = dumb25519.Z
Gi = PointVector([hash_to_point('pybullet Gi ' + str(i)) for i in range(max_MN)])
Hi = PointVector([hash_to_point('pybullet Hi ' + str(i)) for i in range(max_MN)])
# set up weighted aggregates
y0 = Scalar(0)
y1 = Scalar(0)
z1 = Scalar(0)
z3 = Scalar(0)
z4 = [Scalar(0)]*max_MN
z5 = [Scalar(0)]*max_MN
scalars = ScalarVector([]) # for final check
points = PointVector([]) # for final check
# run through each proof
for proof in proofs:
tr = transcript.Transcript('Bulletproof')
V = proof.V
A = proof.A
S = proof.S
T1 = proof.T1
T2 = proof.T2
taux = proof.taux
mu = proof.mu
L = proof.L
R = proof.R
a = proof.a
b = proof.b
t = proof.t
# get size information
M = 2**len(L)/N
# weighting factors for batching
weight_y = random_scalar()
weight_z = random_scalar()
if weight_y == Scalar(0) or weight_z == Scalar(0):
raise ArithmeticError
# reconstruct challenges
for v in V:
tr.update(v)
tr.update(A)
tr.update(S)
y = tr.challenge()
if y == Scalar(0):
raise ArithmeticError
y_inv = y.invert()
z = tr.challenge()
if z == Scalar(0):
raise ArithmeticError
tr.update(T1)
tr.update(T2)
x = tr.challenge()
if x == Scalar(0):
raise ArithmeticError
tr.update(taux)
tr.update(mu)
tr.update(t)
x_ip = tr.challenge()
if x_ip == Scalar(0):
raise ArithmeticError
y0 += taux*weight_y
k = (z-z**2)*sum_scalar(y,M*N)
for j in range(1,M+1):
k -= (z**(j+2))*sum_scalar(Scalar(2),N)
y1 += (t-k)*weight_y
for j in range(M):
scalars.append(z**(j+2)*weight_y)
points.append(V[j]*Scalar(8))
scalars.append(x*weight_y)
points.append(T1*Scalar(8))
scalars.append(x**2*weight_y)
points.append(T2*Scalar(8))
scalars.append(weight_z)
points.append(A*Scalar(8))
scalars.append(x*weight_z)
points.append(S*Scalar(8))
# inner product
W = ScalarVector([])
for i in range(len(L)):
tr.update(L[i])
tr.update(R[i])
W.append(tr.challenge())
if W[i] == Scalar(0):
raise ArithmeticError
W_inv = W.invert()
for i in range(M*N):
index = i
g = a
h = b*((y_inv)**i)
for j in range(len(L)-1,-1,-1):
J = len(W)-j-1
base_power = 2**j
if index/base_power == 0:
g *= W_inv[J]
h *= W[J]
else:
g *= W[J]
h *= W_inv[J]
index -= base_power
g += z
h -= (z*(y**i) + (z**(2+i/N))*(Scalar(2)**(i%N)))*((y_inv)**i)
z4[i] += g*weight_z
z5[i] += h*weight_z
z1 += mu*weight_z
for i in range(len(L)):
scalars.append(W[i]**2*weight_z)
points.append(L[i]*Scalar(8))
scalars.append(W_inv[i]**2*weight_z)
points.append(R[i]*Scalar(8))
z3 += (t-a*b)*x_ip*weight_z
# now check all proofs together
scalars.append(-y0-z1)
points.append(Gc)
scalars.append(-y1+z3)
points.append(Hc)
for i in range(max_MN):
scalars.append(-z4[i])
points.append(Gi[i])
scalars.append(-z5[i])
points.append(Hi[i])
if not dumb25519.multiexp(scalars,points) == Z:
raise ArithmeticError('Bad verification!')
return True
def verify(proofs,N):
# determine the length of the longest proof
max_MN = 2**max([len(proof[7]) for proof in proofs])
# curve points
Z = dumb25519.Z
G = dumb25519.G
H = hash_to_point('pybullet H')
Gi = PointVector([hash_to_point('pybullet Gi ' + str(i)) for i in range(max_MN)])
Hi = PointVector([hash_to_point('pybullet Hi ' + str(i)) for i in range(max_MN)])
# set up weighted aggregates
y0 = Scalar(0)
y1 = Scalar(0)
z1 = Scalar(0)
z3 = Scalar(0)
z4 = [Scalar(0)]*max_MN
z5 = [Scalar(0)]*max_MN
scalars = ScalarVector([]) # for final check
points = PointVector([]) # for final check
# run through each proof
for proof in proofs:
clear_cache()
V,A,S,T1,T2,taux,mu,L,R,a,b,t = proof
# get size information
M = 2**len(L)/N
# weighting factors for batching
weight_y = random_scalar()
weight_z = random_scalar()
if weight_y == Scalar(0) or weight_z == Scalar(0):
raise ArithmeticError
# reconstruct all challenges
for v in V:
mash(v)
mash(A)
mash(S)
if cache == Scalar(0):
raise ArithmeticError
y = cache
y_inv = y.invert()
mash('')
if cache == Scalar(0):
raise ArithmeticError
z = cache
mash(T1)
mash(T2)
if cache == Scalar(0):
raise ArithmeticError
x = cache
mash(taux)
mash(mu)
mash(t)
if cache == Scalar(0):
raise ArithmeticError
x_ip = cache
y0 += taux*weight_y
k = (z-z**2)*sum_scalar(y,M*N)
for j in range(1,M+1):
k -= (z**(j+2))*sum_scalar(Scalar(2),N)
y1 += (t-k)*weight_y
for j in range(M):
scalars.append(z**(j+2)*weight_y)
points.append(V[j]*Scalar(8))
scalars.append(x*weight_y)
points.append(T1*Scalar(8))
scalars.append(x**2*weight_y)
points.append(T2*Scalar(8))
scalars.append(weight_z)
points.append(A*Scalar(8))
scalars.append(x*weight_z)
points.append(S*Scalar(8))
# inner product
W = ScalarVector([])
for i in range(len(L)):
mash(L[i])
mash(R[i])
if cache == Scalar(0):
raise ArithmeticError
W.append(cache)
W_inv = W.invert()
for i in range(M*N):
index = i
g = a
h = b*((y_inv)**i)
for j in range(len(L)-1,-1,-1):
J = len(W)-j-1
base_power = 2**j
if index/base_power == 0:
g *= W_inv[J]
h *= W[J]
else:
g *= W[J]
h *= W_inv[J]
index -= base_power
g += z
h -= (z*(y**i) + (z**(2+i/N))*(Scalar(2)**(i%N)))*((y_inv)**i)
z4[i] += g*weight_z
z5[i] += h*weight_z
z1 += mu*weight_z
for i in range(len(L)):
scalars.append(W[i]**2*weight_z)
points.append(L[i]*Scalar(8))
scalars.append(W_inv[i]**2*weight_z)
points.append(R[i]*Scalar(8))
z3 += (t-a*b)*x_ip*weight_z
# now check all proofs together
scalars.append(-y0-z1)
points.append(G)
scalars.append(-y1+z3)
points.append(H)
for i in range(max_MN):
scalars.append(-z4[i])
points.append(Gi[i])
scalars.append(-z5[i])
points.append(Hi[i])
if not dumb25519.multiexp(scalars,points) == Z:
raise ArithmeticError('Bad z check!')
return True
def test_8_random(self):
data = [[random_point(),random_scalar()] for i in range(8)]
result = Z
for datum in data:
result += datum[0]*datum[1]
self.assertEqual(dumb25519.multiexp(data),result)
def verify(proofs,N):
# determine the length of the longest proof
max_MN = 2**max([len(proof[7]) for proof in proofs])
# curve points
Z = dumb25519.Z
G = dumb25519.G
H = dumb25519.H
Gi = PointVector([hash_to_point('pybullet Gi ' + str(i)) for i in range(max_MN)])
Hi = PointVector([hash_to_point('pybullet Hi ' + str(i)) for i in range(max_MN)])
# verify that all points are in the correct subgroup
for item in dumb25519.flatten(proofs):
if not isinstance(item,Point):
continue
if not item*Scalar(dumb25519.l) == Z:
raise ArithmeticError
# set up weighted aggregates
y0 = Scalar(0)
y1 = Scalar(0)
Y2 = Z
Y3 = Z
Y4 = Z
Z0 = Z
z1 = Scalar(0)
Z2 = Z
z3 = Scalar(0)
z4 = [Scalar(0)]*max_MN
z5 = [Scalar(0)]*max_MN
# run through each proof
for proof in proofs:
clear_cache()
V,A,S,T1,T2,taux,mu,L,R,a,b,t = proof
# get size information
M = 2**len(L)/N
# weighting factor for batching
w = random_scalar()
# reconstruct all challenges
for v in V:
mash(v)
mash(A)
mash(S)
y = cache
mash('')
z = cache
mash(T1)
mash(T2)
x = cache
mash(taux)
mash(mu)
mash(t)
x_ip = cache
y0 += taux*w
k = (z-z**2)*sum_scalar(y,M*N)
for j in range(1,M+1):
k -= (z**(j+2))*sum_scalar(Scalar(2),N)
y1 += (t-k)*w
Temp = Z
for j in range(M):
Temp += V[j]*(z**(j+2)*Scalar(8))
Y2 += Temp*w
Y3 += T1*(x*w*Scalar(8))
Y4 += T2*((x**2)*w*Scalar(8))
Z0 += (A*Scalar(8)+S*(x*Scalar(8)))*w
# inner product
W = []
for i in range(len(L)):
mash(L[i])
mash(R[i])
W.append(cache)
for i in range(M*N):
index = i
g = a
h = b*((y.invert())**i)
for j in range(len(L)-1,-1,-1):
J = len(W)-j-1
base_power = 2**j
if index/base_power == 0:
g *= W[J].invert()
h *= W[J]
else:
g *= W[J]
h *= W[J].invert()
index -= base_power
g += z
h -= (z*(y**i) + (z**(2+i/N))*(Scalar(2)**(i%N)))*((y.invert())**i)
z4[i] += g*w
z5[i] += h*w
z1 += mu*w
Multiexp = []
for i in range(len(L)):
Multiexp.append([L[i],Scalar(8)*(W[i]**2)])
Multiexp.append([R[i],Scalar(8)*(W[i].invert()**2)])
Z2 += dumb25519.multiexp(Multiexp)*w
z3 += (t-a*b)*x_ip*w
# now check all proofs together
if not G*y0 + H*y1 - Y2 - Y3 - Y4 == Z:
raise ArithmeticError('Bad y check!')
Multiexp = [[Z0,Scalar(1)],[G,-z1],[Z2,Scalar(1)],[H,z3]]
for i in range(max_MN):
Multiexp.append([Gi[i],-z4[i]])
Multiexp.append([Hi[i],-z5[i]])
if not dumb25519.multiexp(Multiexp) == Z:
raise ArithmeticError('Bad z check!')
return True
def test_2_G_2_G_n1(self):
data = [[G,Scalar(2)],[G,Scalar(-1)]]
self.assertEqual(dumb25519.multiexp(data),G)
def test_2_G_1_H_2(self):
data = [[G,Scalar(1)],[H,Scalar(2)]]
self.assertEqual(dumb25519.multiexp(data),G+H*Scalar(2))
def test_1_G_2(self):
data = [[G,Scalar(2)]]
self.assertEqual(dumb25519.multiexp(data),G*Scalar(2))
def test_1_G_0(self):
data = [[G,Scalar(0)]]
self.assertEqual(dumb25519.multiexp(data),Z)
def test_0(self):
self.assertEqual(dumb25519.multiexp([]),Z)
