def test_and_dlrne_binding_1():
secrets, secret_values, secret_dict = get_secrets(4)
generators = make_generators(4)
lhs_values = [x * g for x, g in zip(secret_values, generators)]
p1 = DLNotEqual(
[lhs_values[0], generators[0]],
[lhs_values[1], generators[1]],
secrets[0],
bind=True,
)
p2 = DLRep(lhs_values[0], secrets[0] * generators[0])
andp = p1 & p2
p1_prime = DLNotEqual(
[lhs_values[0], generators[0]],
[lhs_values[1], generators[1]],
secrets[0],
bind=True,
)
p2_prime = DLRep(lhs_values[0],
Secret(name=secrets[0].name) * generators[0])
andp_prime = p1_prime & p2_prime
protocol = SigmaProtocol(andp_prime.get_verifier(),
andp.get_prover(secret_dict))
assert protocol.verify()
def params(group):
n1 = 3
n2 = 4
generators1 = make_generators(n1)
generators2 = make_generators(n2)
x0 = Secret()
x1 = Secret()
x2 = Secret()
x3 = Secret()
x4 = Secret()
x5 = Secret()
secrets = [x0, x1, x2, x3, x4, x5]
secrets_dict = dict([
(x0, Bn(1)),
(x1, Bn(2)),
(x2, Bn(5)),
(x3, Bn(100)),
(x4, Bn(43)),
(x5, Bn(10)),
])
sum_1 = group.wsum([secrets_dict[x0], secrets_dict[x1], secrets_dict[x2]],
generators1)
secrets_2 = [secrets_dict[x0]]
for i in range(3, 6):
secrets_2.append(secrets_dict[secrets[i]])
sum_2 = group.wsum(secrets_2, generators2)
p1 = DLRep(sum_1, wsum_secrets([x0, x1, x2], generators1))
p2 = DLRep(sum_2, wsum_secrets([x0, x3, x4, x5], generators2))
return p1, p2, secrets_dict
def test_and_dlrne_does_not_fail_on_same_dl_when_not_binding():
"""
Prove (H0 = h0*x, H1 != h1*x), H2 = h2*x with same secret name x. Should not be detected as
binding is off by default.
"""
secrets, secret_values, secret_dict = get_secrets(4)
generators = make_generators(4)
lhs_values = [x * g for x, g in zip(secret_values, generators)]
y3 = secret_values[2] * generators[3]
s0 = secrets[0]
p1 = DLNotEqual([lhs_values[0], generators[0]],
[lhs_values[1], generators[1]], s0)
p2 = DLRep(lhs_values[2], s0 * generators[2])
andp = p1 & p2
s0_prime = Secret(name=secrets[0].name)
p1_prime = DLNotEqual([lhs_values[0], generators[0]],
[lhs_values[1], generators[1]], s0_prime)
p2_prime = DLRep(lhs_values[2], s0_prime * generators[2])
andp_prime = p1_prime & p2_prime
prov = andp.get_prover(secret_dict)
prov.subs[1].secret_values[s0] = secret_values[2]
protocol = SigmaProtocol(andp_prime.get_verifier(), prov)
assert protocol.verify()
def test_and_proof_partially_defined_secrets():
generators = make_generators(2)
x = Secret(value=4)
x2 = Secret()
p1 = DLRep(4 * generators[0], x * generators[0])
p2 = DLRep(3 * generators[1], x2 * generators[1])
andp = p1 & p2
tr = andp.prove({x2: 3})
assert andp.verify(tr)
def test_multiple_and_dlrep_fails_on_bad_secret_when_binding():
secrets, secret_values, secret_dict = get_secrets(4)
generators = make_generators(4)
lhs_values = [x * g for x, g in zip(secret_values, generators)]
p1 = DLNotEqual(
[lhs_values[0], generators[0]],
[lhs_values[1], generators[1]],
secrets[0],
bind=True,
)
p2 = DLRep(lhs_values[0], secrets[0] * generators[0])
p3 = DLNotEqual(
[lhs_values[2], generators[2]],
[lhs_values[1], generators[1]],
secrets[2],
bind=True,
)
p4 = DLNotEqual(
[lhs_values[1], generators[1]],
[lhs_values[3], generators[3]],
secrets[0],
bind=True,
)
andp = p1 & p2 & p3 & p4
p11 = DLNotEqual(
[lhs_values[0], generators[0]],
[lhs_values[1], generators[1]],
secrets[0],
bind=True,
)
p21 = DLRep(lhs_values[0], secrets[0] * generators[0])
p31 = DLNotEqual(
[lhs_values[2], generators[2]],
[lhs_values[1], generators[1]],
secrets[2],
bind=True,
)
p41 = DLNotEqual(
[lhs_values[1], generators[1]],
[lhs_values[3], generators[3]],
secrets[0],
bind=True,
)
andp1 = p11 & p21 & p31 & p41
prov = andp.get_prover(secret_dict)
prov.subs[1].secret_values[secrets[0]] = secret_values[1]
protocol = SigmaProtocol(andp1.get_verifier(), prov)
with pytest.raises(ValidationError):
protocol.verify()
def prove_values(self, bpriv, reveal_mask=None):
"""A nizk proof of opening with the revealed values.
The proof contains the raw value of all revealed values. This protocol
does not reveal any information about non-revealed values.
Error:
Either reveal_mask should be None or have the same size of private values.
Args:
bpriv (BlPedersenPrivate): values and randomness.
reveal_mask (boolean []): reveals value[i] iff reveal_mask[i]
Optional: mask=None -> reveal nothing
Returns: (BlPedersenProof): a nizk proof for commitment (self)
"""
param = bpriv.param
if reveal_mask is None:
reveal_mask = len(bpriv.values) * [False]
if len(reveal_mask) != len(bpriv.values):
raise Exception(
'The size of reveal mask does not match the number of attributes'
)
# randomness
expr_bl_z = bpriv.blindness_rand * param.Z
expr_bl_h = bpriv.blindness_rand * param.H
expr_bl_h2 = bpriv.blindness_rand * param.H_2
bl_h, bl_h2 = expr_bl_h.eval(), expr_bl_h2.eval()
stmt = (DLRep(self.bl_z, expr_bl_z) & DLRep(bl_h, expr_bl_h)
& DLRep(bl_h2, expr_bl_h2))
# attributes
bl_hi = list()
for i in range(len(bpriv.values)):
expr = bpriv.blindness_rand * param.HS[i]
bl_hi.append(expr.eval())
stmt = stmt & DLRep(bl_hi[i], expr)
# proof
revealed_values = list()
revealed_acc = param.group.infinite()
expr_bl_commit = bpriv.rand * bl_h + bpriv.rand_2 * bl_h2
for i in range(len(bpriv.values)):
if reveal_mask[i]:
revealed_values.append(bpriv.raw_values[i])
revealed_acc += bpriv.values[i].value * bl_hi[i]
else:
revealed_values.append(None)
expr_bl_commit += bpriv.values[i] * bl_hi[i]
stmt = stmt & DLRep(self.bl_commit - revealed_acc, expr_bl_commit)
bproof = BlPedersenProof(bl_h=bl_h,
bl_h2=bl_h2,
bl_hi=bl_hi,
revealed_values=revealed_values,
nizk_proof=stmt.prove())
return bproof
def test_and_proof_with_complex_expression(group):
g = group.generator()
g1 = 2 * g
g2 = 5 * g
g3 = 10 * g
x1 = Secret()
x2 = Secret()
x3 = Secret()
proof = DLRep(10 * g1 + 15 * g2, x1 * g1 + x2 * g2) & DLRep(
15 * g1 + 35 * g3, x2 * g1 + x3 * g3)
prover = proof.get_prover({x1: 10, x2: 15, x3: 35})
verifier = proof.get_verifier()
assert verify(verifier, prover)
def test_and_proof_simulation_2(group):
n = 3
secret_values = [Bn(i) for i in range(n)]
secrets = [Secret() for _ in range(n)]
generators = make_generators(n, group)
lhs = group.wsum(secret_values, generators)
subproof1 = DLRep(lhs, wsum_secrets(secrets, generators))
subproof2 = DLRep(lhs, wsum_secrets(secrets, generators))
andp = AndProofStmt(subproof1, subproof2)
tr = andp.simulate()
assert andp.verify_simulation_consistency(tr)
assert not andp.verify(tr)
def test_and_proof_simulation_1(group):
n = 3
secret_values = [Bn(i) for i in range(n)]
secrets = [Secret() for _ in range(n)]
generators = make_generators(n, group)
lhs = group.wsum(secret_values, generators)
subproof1 = DLRep(lhs, wsum_secrets(secrets, generators))
subproof2 = DLRep(lhs, wsum_secrets(secrets, generators))
andp = AndProofStmt(subproof1, subproof2)
andv = andp.get_verifier()
tr = andp.simulate_proof()
tr.stmt_hash = andp.prehash_statement().digest()
assert not andv.verify_nizk(tr)
def test_multiple_and_dlrep_binding():
secrets = get_secrets_new(4)
generators = make_generators(4)
lhs_values = [x.value * g for x, g in zip(secrets, generators)]
p1 = DLNotEqual(
[lhs_values[0], generators[0]],
[lhs_values[1], generators[1]],
secrets[0],
bind=False,
)
p2 = DLRep(lhs_values[2], secrets[2] * generators[2])
p3 = DLNotEqual(
[lhs_values[2], generators[2]],
[lhs_values[1], generators[1]],
secrets[2],
bind=True,
)
p4 = DLNotEqual(
[lhs_values[1], generators[1]],
[lhs_values[3], generators[3]],
secrets[1],
bind=True,
)
andp = p1 & p2 & p3 & p4
s0 = Secret()
s2 = Secret()
p1prime = DLNotEqual([lhs_values[0], generators[0]],
[lhs_values[1], generators[1]],
s0,
bind=False)
p2prime = DLRep(lhs_values[2], s2 * generators[2])
p3prime = DLNotEqual([lhs_values[2], generators[2]],
[lhs_values[1], generators[1]],
s2,
bind=True)
# Note difference: p4prime binds s0 instead of secrets[1] in the original proof
p4prime = DLNotEqual([lhs_values[1], generators[1]],
[lhs_values[3], generators[3]],
s0,
bind=True)
andp1 = p1prime & p2prime & p3prime & p4prime
protocol = SigmaProtocol(andp1.get_verifier(), andp.get_prover())
assert protocol.verify()
def verify_proof(self, bc_param, bproof):
"""Verify a PedersenProof for this commitment.
Important: besides verifying the proof, you should verify the parameters.
Args:
bc_param (BlPedersenParam): commitment parameters
bproof (BlPedersenProof): a nizk proof for self
Returns:
boolean: pass/fail
"""
if bc_param.get_param_num() < len(bproof.bl_hi):
bc_param.expand_params_len(len(bproof.bl_hi))
bl_rand_sec = Secret(name="blindness_rand")
# randomness
expr_bl_z = bl_rand_sec * bc_param.Z
expr_bl_h = bl_rand_sec * bc_param.H
expr_bl_h2 = bl_rand_sec * bc_param.H_2
stmt = (DLRep(self.bl_z, expr_bl_z) & DLRep(bproof.bl_h, expr_bl_h)
& DLRep(bproof.bl_h2, expr_bl_h2))
# attributes
for i in range(len(bproof.bl_hi)):
expr = bl_rand_sec * bc_param.HS[i]
stmt = stmt & DLRep(bproof.bl_hi[i], expr)
# proof
revealed_acc = bc_param.group.infinite()
expr_bl_commit = Secret(name="rand") * bproof.bl_h + Secret(
name="rand_2") * bproof.bl_h2
for i in range(len(bproof.bl_hi)):
if bproof.revealed_values[i] is None:
expr_bl_commit += Secret(name=f"val_{i}") * bproof.bl_hi[i]
else:
val = bc_param.process_raw_value(bproof.revealed_values[i])
revealed_acc += val * bproof.bl_hi[i]
stmt = stmt & DLRep(self.bl_commit - revealed_acc, expr_bl_commit)
# Having an invalid revealed secret leads to different
# {commit-revealed_acc} value between prover and verifier. Since this
# value is a zksk.statement constant, the mismatch results in a
# StatementMismatch exception. verify_proof checks for this exception
# and convert it to False
try:
is_valid = stmt.verify(bproof.nizk_proof)
except StatementMismatch:
return False
return is_valid
def test_multiple_or_proof_infix_operator(group, params):
p1, p2, secrets = params
g = group.generator()
x10 = Secret()
secrets.update({x10: 13})
orproof = p1 | p2 | DLRep(13 * g, x10 * g)
assert verify_proof(orproof, secrets)
def test_multiple_or_proofs(group, params):
p1, p2, secrets = params
g = group.generator()
x10 = Secret()
secrets.update({x10: 13})
orproof = OrProofStmt(p1, OrProofStmt(p2, DLRep(13 * g, x10 * g)))
assert verify_proof(orproof, secrets)
def test_multiple_dlrne_simulation():
secrets, secret_values, secret_dict = get_secrets(4)
generators = make_generators(4)
lhs_values = [x * g for x, g in zip(secret_values, generators)]
p1 = DLNotEqual(
[lhs_values[0], generators[0]],
[lhs_values[1], generators[1]],
secrets[0],
bind=False,
)
p2 = DLRep(lhs_values[2], secrets[2] * generators[2])
p3 = DLNotEqual(
[lhs_values[2], generators[2]],
[lhs_values[1], generators[1]],
secrets[2],
bind=True,
)
p4 = DLNotEqual(
[lhs_values[1], generators[1]],
[lhs_values[3], generators[3]],
secrets[0],
bind=True,
)
andp = p1 & p2 & p3 & p4
tr = andp.simulate()
assert andp.verify_simulation_consistency(tr)
assert not andp.verify(tr)
def test_dlrep_or_rangeproof(group):
g, h = make_generators(2)
x = Secret(9)
y = Secret(42)
z = Secret(40)
c = x.value * g + y.value * h
c2 = z.value * g + y.value * h
stmt1 = DLRep(c, x * g + y * h) & RangeStmt(c, g, h, 0, 50, x, y)
stmt2 = DLRep(c2, z * g + y * h) & RangeStmt(c2, g, h, 0, 50, z, y)
stmt1.set_simulated()
or_stmt = OrProofStmt(stmt1, stmt2)
nizk = or_stmt.prove()
assert or_stmt.verify(nizk)
def test_and_or_proof_composition(params):
p1, p2, secrets = params
g1 = 7 * p1.bases[0]
g2 = 8 * p1.bases[0]
xb = Secret(name="xb")
xa = Secret(name="xa")
p0 = DLRep(7 * g1 + 18 * g2, xb * g1 + xa * g2)
secrets[xb] = 7
secrets[xa] = 18
orproof = OrProofStmt(p1, p2)
andp = AndProofStmt(orproof, p0)
andp = AndProofStmt(andp, DLRep(15 * p1.bases[0], Secret(value=15) * p1.bases[0]))
prover = andp.get_prover(secrets)
verifier = andp.get_verifier()
assert verify(verifier, prover)
def test_multiple_or_proofs_composition(group, params):
p1, p2, secrets = params
g = group.generator()
x10 = Secret()
secrets.update({x10: 13})
orp1 = OrProofStmt(p2, p1)
orp2 = OrProofStmt(p1, DLRep(13 * g, x10 * g))
orproof = OrProofStmt(orp1, p2, orp2)
assert verify_proof(orproof, secrets)
def test_invalid_or_composition_inside_two_or():
r = Secret(10)
g1, g2, g3, g4 = make_generators(4)
st11 = DLRep(r.value * g1, r * g1)
st12 = DLRep(2 * g2, r * g2)
st12.set_simulated()
st1 = st11 | st12
st21 = DLRep(7 * g3, r * g3)
st21.simluation = True
st22 = DLRep(r.value * g4, r * g4)
st2 = st21 | st22
st = st1 & st2
with pytest.raises(InvalidSecretsError):
st.prove()
def test_statement_zk_proof() -> None:
vm = sy.VirtualMachine()
client = vm.get_root_client()
sy.load("zksk")
# third party
from zksk import DLRep
from zksk import Secret
from zksk import utils
num = 2
seed = 42
num_sy = sy.lib.python.Int(num)
seed_sy = sy.lib.python.Int(seed)
# Setup: Peggy and Victor agree on two group generators.
G, H = utils.make_generators(num=num, seed=seed)
# Setup: generate a secret randomizer.
r = Secret(utils.get_random_num(bits=128))
# This is Peggy's secret bit.
top_secret_bit = 1
# A Pedersen commitment to the secret bit.
C = top_secret_bit * G + r.value * H
# Peggy's definition of the proof statement, and proof generation.
# (The first or-clause corresponds to the secret value 0, and the second to the value 1. Because
# the real value of the bit is 1, the clause that corresponds to zero is marked as simulated.)
stmt = DLRep(C, r * H, simulated=True) | DLRep(C - G, r * H)
zk_proof = stmt.prove()
# send over the network and get back
num_ptr = num_sy.send(client)
seed_prt = seed_sy.send(client)
c_ptr = C.send(client)
zk_proof_ptr = zk_proof.send(client)
num2 = num_ptr.get().upcast()
seed2 = seed_prt.get().upcast()
C2 = c_ptr.get()
zk_proof2 = zk_proof_ptr.get()
# Setup: get the agreed group generators.
G, H = utils.make_generators(num=num2, seed=seed2)
# Setup: define a randomizer with an unknown value.
r = Secret()
stmt = DLRep(C2, r * H) | DLRep(C2 - G, r * H)
assert stmt.verify(zk_proof2)
def test_dlrep_and_dlrne_fails_on_same_dl_when_binding():
"""
Prove (H0 = h0*x, H1 != h1*x), H2 = h2*x with same secret name x. Should be detected as
binding is on.
"""
secrets, secret_values, secret_dict = get_secrets(4)
generators = make_generators(4)
lhs_values = [x * g for x, g in zip(secret_values, generators)]
y3 = secret_values[2] * generators[3]
p1 = DLNotEqual(
[lhs_values[0], generators[0]],
[lhs_values[1], generators[1]],
secrets[0],
bind=True,
)
p2 = DLRep(lhs_values[2], secrets[0] * generators[2])
andp = p1 & p2
# Twin proof
s0_prime = Secret(name=secrets[0].name)
p1_prime = DLNotEqual(
[lhs_values[0], generators[0]],
[lhs_values[1], generators[1]],
s0_prime,
bind=True,
)
p2_prime = DLRep(lhs_values[2], s0_prime * generators[2])
andp_prime = p1_prime & p2_prime
prov = andp.get_prover(secret_dict)
prov.subs[1].secret_values[secrets[0]] = secret_values[2]
ver = andp_prime.get_verifier()
ver.process_precommitment(prov.precommit())
com = prov.commit()
chal = ver.send_challenge(com)
resp = prov.compute_response(chal)
with pytest.raises(ValidationError):
ver.verify(resp)
def test_and_dlrne_non_interactive_1(group):
g = group.generator()
x = Secret(value=3)
y = 3 * g
y2 = 397474 * g
g2 = 1397 * g
pr = DLNotEqual([y, g], [y2, g2], x, bind=True)
p2 = DLNotEqual([2 * y, 2 * g], [y2, g2], x, bind=True)
andp = pr & p2 & DLRep(y, x * g)
tr = andp.prove()
assert andp.verify(tr)
def test_and_dlrne_non_interactive_2():
secrets, secret_values, secret_dict = get_secrets(4)
generators = make_generators(4)
lhs_values = [x * g for x, g in zip(secret_values, generators)]
p1 = DLNotEqual(
[lhs_values[0], generators[0]],
[lhs_values[1], generators[1]],
secrets[0],
bind=True,
)
p2 = DLRep(lhs_values[0], secrets[0] * generators[0])
p3 = DLNotEqual(
[lhs_values[2], generators[2]],
[lhs_values[1], generators[1]],
secrets[2],
bind=True,
)
andp = p1 & p2 & p3
s0 = Secret()
s2 = Secret()
p11 = DLNotEqual([lhs_values[0], generators[0]],
[lhs_values[1], generators[1]],
s0,
bind=True)
p21 = DLRep(lhs_values[0], s0 * generators[0])
p31 = DLNotEqual([lhs_values[2], generators[2]],
[lhs_values[1], generators[1]],
s2,
bind=True)
andp1 = p11 & p21 & p31
tr = andp.prove(secret_dict)
assert andp1.verify(tr)
def test_and_proof_fails_when_bases_belong_to_different_groups(group):
"""
An alien EcPt is inserted in the generators
"""
g1 = group.generator()
other_group = EcGroup(706)
assert group != other_group
g2 = other_group.generator()
x = Secret(value=Bn(42))
y1 = group.wsum([x.value], [g1])
y2 = other_group.wsum([x.value], [g2])
p1 = DLRep(y1, wsum_secrets([x], [g1]))
p2 = DLRep(y2, wsum_secrets([x], [g2]))
and_proof = AndProofStmt(p1, p2)
prover = and_proof.get_prover()
verifier = and_proof.get_verifier()
# An exception should be raised because of a shared secrets linked to two different groups
with pytest.raises(GroupMismatchError):
verify(verifier, prover)
def test_nizk_serde() -> None:
vm = sy.VirtualMachine()
client = vm.get_root_client()
# third party
from zksk import DLRep
from zksk import Secret
from zksk import utils
sy.load("zksk")
num = 2
seed = 42
G, H = utils.make_generators(num=num, seed=seed)
# Setup: generate a secret randomizer.
r = Secret(utils.get_random_num(bits=128))
# This is Peggy's secret bit.
top_secret_bit = 1
# A Pedersen commitment to the secret bit.
C = top_secret_bit * G + r.value * H
# Peggy's definition of the proof statement, and proof generation.
# (The first or-clause corresponds to the secret value 0, and the second to the value 1. Because
# the real value of the bit is 1, the clause that corresponds to zero is marked as simulated.)
stmt = DLRep(C, r * H, simulated=True) | DLRep(C - G, r * H)
# zksk.base.NIZK
zk_proof = stmt.prove()
# test serde
zk_proof_ptr = zk_proof.send(client)
zk_proof2 = zk_proof_ptr.get()
assert zk_proof == zk_proof2
def test_malicious_and_proofs():
x0 = Secret()
x2 = Secret()
x1 = Secret()
generators = make_generators(3)
g1 = generators[0]
g2 = generators[1]
g3 = generators[2]
secret_dict = {x0: 3, x2: 50, x1: 12}
mal_secret_dict = {x0: 3, x2: 51}
andp = AndProofStmt(
DLRep(12 * g1 + 50 * g2, x1 * g1 + x2 * g2),
DLRep(3 * g3 + 51 * g2, x0 * g1 + x2 * g2),
)
prov = andp.get_prover(secret_dict)
prov.subs[1].secret_values = mal_secret_dict
verif = andp.get_verifier()
com = prov.commit()
chal = verif.send_challenge(com)
resp = prov.compute_response(chal)
with pytest.raises(ValidationError):
verif.verify(resp)
def test_or_and_proof_composition(params):
p1, p2, secrets = params
andp = AndProofStmt(p1, p2)
g1 = 7 * p1.bases[0]
g2 = 8 * p1.bases[0]
xb = Secret(name="xb")
xa = Secret(name="xa")
p0 = DLRep(7 * g1 + 18 * g2, xb * g1 + xa * g2)
secrets[xa] = 7
secrets[Secret(name="xc")] = 18
orproof = OrProofStmt(p0, andp)
prover = orproof.get_prover(secrets)
verifier = orproof.get_verifier()
assert verify(verifier, prover)
def test_invalid_or_composition():
r = Secret(10)
g1, g2, g3 = make_generators(3)
st1 = DLRep(10 * g1, r * g1)
st21 = DLRep(10 * g2, r * g2)
st22 = DLRep(12 * g3, r * g3)
st22.set_simulated()
st2 = st21 | st22
st = st1 & st2
with pytest.raises(InvalidSecretsError):
st.prove()
def ZK_equality(G,H):
##Generate two El-Gamal ciphertexts (C1,C2) and (D1,D2)
# Setup: generate secret randomizers.
# m is the secret bit.
m = Secret(utils.get_random_num(bits=2))
r1 = Secret(utils.get_random_num(bits=128))
r2 = Secret(utils.get_random_num(bits=128))
C1 = r1.value*G
#print("this is C1:", C1)
C2 = r1.value * H + m.value * G
D1 = r2.value * G
D2 = r2.value * H + m.value * G
##Generate a NIZK proving equality of the plaintexts
stmt = DLRep(C1,r1*G) & DLRep(C2,r1*H+m*G) & DLRep(D1,r2*G) & DLRep(D2,r2*H+m*G)
zk_proof = stmt.prove()
#Return two ciphertexts and the proof
return (C1,C2), (D1,D2), zk_proof
g3 = group.hash_to_point(b"three")
# Preparing the secrets.
# In practice, they probably should be big integers (petlib.bn.Bn)
x0 = Secret()
x1 = Secret()
x2 = Secret()
# Set up the proof statement.
# First, compute the values, "left-hand side".
y1 = 4 * g0 + 5 * g1
y2 = 4 * g2 + 7 * g3
# Next, create the proof statement.
stmt = DLRep(y1, x0 * g0 + x1 * g1) \
& DLRep(y2, x0 * g2 + x2 * g3)
# This is an equivalent way to create the proof statement above.
stmt_1 = DLRep(y1, x0 * g0 + x1 * g1)
stmt_2 = DLRep(y2, x0 * g2 + x2 * g3)
equivalent_stmt = AndProofStmt(stmt_1, stmt_2)
assert stmt.get_proof_id() == equivalent_stmt.get_proof_id()
# Simulate the prover and verifier interacting.
prover = stmt.get_prover({x0: 4, x1: 5, x2: 7})
verifier = stmt.get_verifier()
commitment = prover.commit()
from zksk import Secret, DLRep group = EcGroup() # Create the base points on the curve. g0 = group.hash_to_point(b"one") g1 = group.hash_to_point(b"two") g2 = group.hash_to_point(b"three") # Preparing the secrets. # In practice, they probably should be big integers (petlib.bn.Bn) x0 = Secret(value=3) x1 = Secret(value=40) x2 = Secret(value=50) # Set up the proof statement. y0 = x0.value * g0 y1 = x1.value * g1 y2 = x2.value * g2 stmt = (DLRep(y0, x0 * g0) | DLRep(y1, x1 * g1)) & DLRep(y2, x2 * g2) # Execute the protocol. prover = stmt.get_prover() verifier = stmt.get_verifier() commitment = prover.commit() challenge = verifier.send_challenge(commitment) response = prover.compute_response(challenge) assert verifier.verify(response)
