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Adding vector sizes into transcript, inner product domain separator m…
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…oved up
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@levonpetrosyan93
levonpetrosyan93 committed Apr 13, 2021
1 parent 905dee5 commit c1a84ce
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Showing 11 changed files with 71 additions and 65 deletions.
8 changes: 4 additions & 4 deletions src/lelantus.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -109,9 +109,9 @@ void GenerateMintSchnorrProof(const lelantus::PrivateCoin& coin, CDataStream& s
unique_ptr<ChallengeGenerator> challengeGenerator;
if (afterFixes) {
// start to use CHash256 which is more secure
challengeGenerator = std::make_unique<ChallengeGeneratorImpl<CHash256>>();
challengeGenerator = std::make_unique<ChallengeGeneratorImpl<CHash256>>(1);
} else {
challengeGenerator = std::make_unique<ChallengeGeneratorImpl<CSHA256>>();
challengeGenerator = std::make_unique<ChallengeGeneratorImpl<CSHA256>>(0);
}

// commit (G^s*H1^v*H2^r), comm (G^s*H2^r), and H1^v are used in challenge generation if nLelantusFixesStartBlock is passed
Expand All @@ -132,9 +132,9 @@ bool VerifyMintSchnorrProof(const uint64_t& v, const secp_primitives::GroupEleme
unique_ptr<ChallengeGenerator> challengeGenerator;
if (afterFixes) {
// start to use CHash256 which is more secure
challengeGenerator = std::make_unique<ChallengeGeneratorImpl<CHash256>>();
challengeGenerator = std::make_unique<ChallengeGeneratorImpl<CHash256>>(1);
} else {
challengeGenerator = std::make_unique<ChallengeGeneratorImpl<CSHA256>>();
challengeGenerator = std::make_unique<ChallengeGeneratorImpl<CSHA256>>(0);
}

// commit (G^s*H1^v*H2^r), comm (G^s*H2^r), and H1^v are used in challenge generation if nLelantusFixesStartBlock is passed
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15 changes: 13 additions & 2 deletions src/liblelantus/challenge_generator_impl.h
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Original file line number Diff line number Diff line change
Expand Up @@ -5,7 +5,7 @@
#include <secp256k1/include/GroupElement.h>
#include "../../crypto/sha256.h"
#include "challenge_generator.h"

#include <iostream>
namespace lelantus {

using namespace secp_primitives;
Expand All @@ -14,7 +14,8 @@ template <class Hasher>
class ChallengeGeneratorImpl : public ChallengeGenerator {

public:
ChallengeGeneratorImpl() {
ChallengeGeneratorImpl(int version_ = 0) {
version = version_;
data.resize(GroupElement::serialize_size);
scalar_data.resize(32);
}
Expand All @@ -25,6 +26,7 @@ class ChallengeGeneratorImpl : public ChallengeGenerator {
}

void add(const std::vector<GroupElement>& group_elements) {
addSize(group_elements.size());
for (size_t i = 0; i < group_elements.size(); ++i) {
add(group_elements[i]);
}
Expand All @@ -36,6 +38,7 @@ class ChallengeGeneratorImpl : public ChallengeGenerator {
}

void add(const std::vector<Scalar>& scalars) {
addSize(scalars.size());
for (size_t i = 0; i < scalars.size(); ++i) {
add(scalars[i]);
}
Expand All @@ -57,6 +60,14 @@ class ChallengeGeneratorImpl : public ChallengeGenerator {
}

private:
void addSize(uint32_t size) {
if (version >= 1) {
std::string s = std::to_string(size);
hash.Write((const unsigned char*)s.c_str(), s.size());
}
}
private:
int version;
Hasher hash;
std::vector<unsigned char> data;
std::vector<unsigned char> scalar_data;
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9 changes: 2 additions & 7 deletions src/liblelantus/innerproduct_proof_generator.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -79,13 +79,8 @@ void InnerProductProofGenerator::generate_proof_util(

// if(version_ >= 2) we should be using CHash256,
// we want to link transcripts from previous iteration in each step, so we are not restarting in that case,
if (version_ >= 2) {
// add domain separator in each step
std::string domain_separator = "INNER_PRODUCT";
std::vector<unsigned char> pre(domain_separator.begin(), domain_separator.end());
challengeGenerator->add(pre);
} else {
challengeGenerator.reset(new ChallengeGeneratorImpl<CSHA256>());
if (version_ < 2) {
challengeGenerator.reset(new ChallengeGeneratorImpl<CSHA256>(0));
}
challengeGenerator->add(group_elements);
challengeGenerator->get_challenge(x);
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18 changes: 4 additions & 14 deletions src/liblelantus/innerproduct_proof_verifier.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -45,13 +45,8 @@ bool InnerProductProofVerifier::verify_util(

// if(version >= 2) we should be using CHash256,
// we want to link transcripts from previous iteration in each step, so we are not restarting in that case,
if (version_ >= 2) {
// add domain separator in each step
std::string domain_separator = "INNER_PRODUCT";
std::vector<unsigned char> pre(domain_separator.begin(), domain_separator.end());
challengeGenerator->add(pre);
} else {
challengeGenerator.reset(new ChallengeGeneratorImpl<CSHA256>());
if (version_ < 2) {
challengeGenerator.reset(new ChallengeGeneratorImpl<CSHA256>(0));
}
challengeGenerator->add(group_elements);
challengeGenerator->get_challenge(x);
Expand Down Expand Up @@ -86,13 +81,8 @@ bool InnerProductProofVerifier::verify_fast_util(

// if(version_ >= 2) we should be using CHash256,
// we want to link transcripts from previous iteration in each step, so we are not restarting in that case,
if (version_ >= 2) {
// add domain separator in each step
std::string domain_separator = "INNER_PRODUCT";
std::vector<unsigned char> pre(domain_separator.begin(), domain_separator.end());
challengeGenerator->add(pre);
} else {
challengeGenerator.reset(new ChallengeGeneratorImpl<CSHA256>());
if (version_ < 2) {
challengeGenerator.reset(new ChallengeGeneratorImpl<CSHA256>(0));
}
challengeGenerator->add(group_elements);
challengeGenerator->get_challenge(x_j[i]);
Expand Down
8 changes: 4 additions & 4 deletions src/liblelantus/lelantus_primitives.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -14,11 +14,11 @@ void LelantusPrimitives::generate_challenge(

std::unique_ptr<ChallengeGenerator> challengeGenerator;
if (domain_separator != "") {
challengeGenerator = std::make_unique<ChallengeGeneratorImpl<CHash256>>();
challengeGenerator = std::make_unique<ChallengeGeneratorImpl<CHash256>>(1);
std::vector<unsigned char> pre(domain_separator.begin(), domain_separator.end());
challengeGenerator->add(pre);
} else {
challengeGenerator = std::make_unique<ChallengeGeneratorImpl<CSHA256>>();
challengeGenerator = std::make_unique<ChallengeGeneratorImpl<CSHA256>>(0);
}

challengeGenerator->add(group_elements);
Expand Down Expand Up @@ -103,7 +103,7 @@ void LelantusPrimitives::generate_Lelantus_challenge(

// starting from LELANTUS_TX_VERSION_4_5 we are using CHash256, and adding domain separator, version, pubkeys and serials into it
if (version >= LELANTUS_TX_VERSION_4_5) {
challengeGenerator = std::make_unique<ChallengeGeneratorImpl<CHash256>>();
challengeGenerator = std::make_unique<ChallengeGeneratorImpl<CHash256>>(1);
std::string domainSeparator = lts + std::to_string(version);
std::vector<unsigned char> pre(domainSeparator.begin(), domainSeparator.end());
challengeGenerator->add(pre);
Expand All @@ -113,7 +113,7 @@ void LelantusPrimitives::generate_Lelantus_challenge(
challengeGenerator->add(pubkey);
challengeGenerator->add(serialNumbers);
} else {
challengeGenerator = std::make_unique<ChallengeGeneratorImpl<CSHA256>>();
challengeGenerator = std::make_unique<ChallengeGeneratorImpl<CSHA256>>(0);
}

if (Cout.size() > 0) {
Expand Down
11 changes: 9 additions & 2 deletions src/liblelantus/range_prover.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -64,14 +64,14 @@ void RangeProver::batch_proof(
Scalar y, z;
unique_ptr<ChallengeGenerator> challengeGenerator;
if (version >= LELANTUS_TX_VERSION_4_5) {
challengeGenerator = std::make_unique<ChallengeGeneratorImpl<CHash256>>();
challengeGenerator = std::make_unique<ChallengeGeneratorImpl<CHash256>>(1);
// add domain separator and transaction version into transcript
std::string domain_separator = "RANGE_PROOF" + std::to_string(version);
std::vector<unsigned char> pre(domain_separator.begin(), domain_separator.end());
challengeGenerator->add(pre);
challengeGenerator->add(commitments);
} else {
challengeGenerator = std::make_unique<ChallengeGeneratorImpl<CSHA256>>();
challengeGenerator = std::make_unique<ChallengeGeneratorImpl<CSHA256>>(0);
}

challengeGenerator->add({proof_out.A, proof_out.S});
Expand Down Expand Up @@ -168,6 +168,13 @@ void RangeProver::batch_proof(
challengeGenerator->add({proof_out.T_x1, proof_out.T_x2, proof_out.u});
challengeGenerator->get_challenge(x_u);

if (version >= LELANTUS_TX_VERSION_4_5) {
// add domain separator in each step
std::string domain_separator = "INNER_PRODUCT";
std::vector<unsigned char> pre(domain_separator.begin(), domain_separator.end());
challengeGenerator->add(pre);
}

// if(inner_product_version >= 2) link range proof data to inner product transcript with passing already filled challengeGenerator
InnerProductProofGenerator.generate_proof(l, r, x_u, challengeGenerator, proof_out.innerProductProof);
}
Expand Down
21 changes: 12 additions & 9 deletions src/liblelantus/range_verifier.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -29,14 +29,14 @@ bool RangeVerifier::verify_batch(const std::vector<GroupElement>& V, const std::
Scalar x, x_u, y, z;
unique_ptr<ChallengeGenerator> challengeGenerator;
if (version >= LELANTUS_TX_VERSION_4_5) {
challengeGenerator = std::make_unique<ChallengeGeneratorImpl<CHash256>>();
challengeGenerator = std::make_unique<ChallengeGeneratorImpl<CHash256>>(1);
// add domain separator and transaction version into transcript
std::string domain_separator = "RANGE_PROOF" + std::to_string(version);
std::vector<unsigned char> pre(domain_separator.begin(), domain_separator.end());
challengeGenerator->add(pre);
challengeGenerator->add(commitments);
} else {
challengeGenerator = std::make_unique<ChallengeGeneratorImpl<CSHA256>>();
challengeGenerator = std::make_unique<ChallengeGeneratorImpl<CSHA256>>(0);
}
challengeGenerator->add({proof.A, proof.S});
challengeGenerator->get_challenge(y);
Expand All @@ -54,19 +54,22 @@ bool RangeVerifier::verify_batch(const std::vector<GroupElement>& V, const std::
std::vector<Scalar> x_j, x_j_inv;
x_j.resize(log_n);
x_j_inv.reserve(log_n);

if (version >= LELANTUS_TX_VERSION_4_5) {
// add domain separator in each step
std::string domain_separator = "INNER_PRODUCT";
std::vector<unsigned char> pre(domain_separator.begin(), domain_separator.end());
challengeGenerator->add(pre);
}

for (int i = 0; i < log_n; ++i)
{
std::vector<GroupElement> group_elements_i = {innerProductProof.L_[i], innerProductProof.R_[i]};

// if(version >= LELANTUS_TX_VERSION_4_5) we should be using CHash256,
// we want to link transcripts from range proof and from previous iteration in each step, so we are not restarting in that case,
if (version >= LELANTUS_TX_VERSION_4_5) {
// add domain separator in each step
std::string domain_separator = "INNER_PRODUCT";
std::vector<unsigned char> pre(domain_separator.begin(), domain_separator.end());
challengeGenerator->add(pre);
} else {
challengeGenerator.reset(new ChallengeGeneratorImpl<CSHA256>());
if (version < LELANTUS_TX_VERSION_4_5) {
challengeGenerator.reset(new ChallengeGeneratorImpl<CSHA256>(0));
}

challengeGenerator->add(group_elements_i);
Expand Down
4 changes: 2 additions & 2 deletions src/liblelantus/schnorr_prover.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -32,7 +32,7 @@ void SchnorrProver::proof(
group_elements = {u, y, a, b};
challengeGenerator->add(pre);
} else {
challengeGenerator.reset(new ChallengeGeneratorImpl<CSHA256>());
challengeGenerator.reset(new ChallengeGeneratorImpl<CSHA256>(0));
}
challengeGenerator->add(group_elements);
challengeGenerator->get_challenge(c);
Expand All @@ -53,7 +53,7 @@ void SchnorrProver::proof(
proof_out.u = u;
Scalar c;

ChallengeGeneratorImpl<CHash256> challengeGenerator;
ChallengeGeneratorImpl<CHash256> challengeGenerator(1);
std::string shts = "SCHNORR_PROOF";
std::vector<unsigned char> pre(shts.begin(), shts.end());
challengeGenerator.add(pre);
Expand Down
4 changes: 2 additions & 2 deletions src/liblelantus/schnorr_verifier.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -25,7 +25,7 @@ bool SchnorrVerifier::verify(
group_elements = {u, y, a, b};
challengeGenerator->add(pre);
} else {
challengeGenerator.reset(new ChallengeGeneratorImpl<CSHA256>());
challengeGenerator.reset(new ChallengeGeneratorImpl<CSHA256>(0));
}
challengeGenerator->add(group_elements);
challengeGenerator->get_challenge(c);
Expand Down Expand Up @@ -53,7 +53,7 @@ bool SchnorrVerifier::verify(
const GroupElement& u = proof.u;
Scalar c;

ChallengeGeneratorImpl<CHash256> challengeGenerator;
ChallengeGeneratorImpl<CHash256> challengeGenerator(1);
std::string shts = "SCHNORR_PROOF";
std::vector<unsigned char> pre(shts.begin(), shts.end());
challengeGenerator.add(pre);
Expand Down
22 changes: 11 additions & 11 deletions src/liblelantus/test/inner_product_test.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -57,7 +57,7 @@ BOOST_AUTO_TEST_CASE(prove_verify_one)

Scalar x;
x.randomize();
unique_ptr<ChallengeGenerator> challengeGenerator = std::make_unique<ChallengeGeneratorImpl<CHash256>>();
unique_ptr<ChallengeGenerator> challengeGenerator = std::make_unique<ChallengeGeneratorImpl<CHash256>>(1);

// generating proofs
Proof proof;
Expand All @@ -74,9 +74,9 @@ BOOST_AUTO_TEST_CASE(prove_verify_one)
BOOST_CHECK_EQUAL(log2_n, proof.R_.size());

// verify
challengeGenerator.reset(new ChallengeGeneratorImpl<CHash256>());
challengeGenerator.reset(new ChallengeGeneratorImpl<CHash256>(1));
BOOST_CHECK(ProofVerifier(gens_g, gens_h, u, ComputePInit(), 2).verify(x, proof, challengeGenerator));
challengeGenerator.reset(new ChallengeGeneratorImpl<CHash256>());
challengeGenerator.reset(new ChallengeGeneratorImpl<CHash256>(1));
BOOST_CHECK(ProofVerifier(gens_g, gens_h, u, ComputePInit(), 2).verify_fast(n, x, proof, challengeGenerator));
}

Expand All @@ -89,7 +89,7 @@ BOOST_AUTO_TEST_CASE(prove_verify)

Scalar x;
x.randomize();
unique_ptr<ChallengeGenerator> challengeGenerator = std::make_unique<ChallengeGeneratorImpl<CHash256>>();
unique_ptr<ChallengeGenerator> challengeGenerator = std::make_unique<ChallengeGeneratorImpl<CHash256>>(1);

// generating proofs
Proof proof;
Expand All @@ -104,9 +104,9 @@ BOOST_AUTO_TEST_CASE(prove_verify)
BOOST_CHECK_EQUAL(log2_n, proof.R_.size());

// verify
challengeGenerator.reset(new ChallengeGeneratorImpl<CHash256>());
challengeGenerator.reset(new ChallengeGeneratorImpl<CHash256>(1));
BOOST_CHECK(ProofVerifier(gens_g, gens_h, u, ComputePInit(), 2).verify(x, proof, challengeGenerator));
challengeGenerator.reset(new ChallengeGeneratorImpl<CHash256>());
challengeGenerator.reset(new ChallengeGeneratorImpl<CHash256>(1));
BOOST_CHECK(ProofVerifier(gens_g, gens_h, u, ComputePInit(), 2).verify_fast(n, x, proof, challengeGenerator));
}

Expand All @@ -119,7 +119,7 @@ BOOST_AUTO_TEST_CASE(fake_proof_not_verify)

Scalar x;
x.randomize();
unique_ptr<ChallengeGenerator> challengeGenerator = std::make_unique<ChallengeGeneratorImpl<CHash256>>();
unique_ptr<ChallengeGenerator> challengeGenerator = std::make_unique<ChallengeGeneratorImpl<CHash256>>(1);

// generating genertor
Proof proof;
Expand All @@ -129,16 +129,16 @@ BOOST_AUTO_TEST_CASE(fake_proof_not_verify)
GroupElement fakeP;
fakeP.randomize();

challengeGenerator.reset(new ChallengeGeneratorImpl<CHash256>());
challengeGenerator.reset(new ChallengeGeneratorImpl<CHash256>(1));
BOOST_CHECK(!ProofVerifier(gens_g, gens_h, u, fakeP, 2).verify(x, proof, challengeGenerator));
challengeGenerator.reset(new ChallengeGeneratorImpl<CHash256>());
challengeGenerator.reset(new ChallengeGeneratorImpl<CHash256>(1));
BOOST_CHECK(!ProofVerifier(gens_g, gens_h, u, fakeP, 2).verify_fast(n, x, proof, challengeGenerator));

// verify with fake proof
auto verify = [&](Scalar const &_x, Proof const &_p) -> void {
challengeGenerator.reset(new ChallengeGeneratorImpl<CHash256>());
challengeGenerator.reset(new ChallengeGeneratorImpl<CHash256>(1));
BOOST_CHECK(!ProofVerifier(gens_g, gens_h, u, ComputePInit(), 2).verify(_x, _p, challengeGenerator));
challengeGenerator.reset(new ChallengeGeneratorImpl<CHash256>());
challengeGenerator.reset(new ChallengeGeneratorImpl<CHash256>(1));
BOOST_CHECK(!ProofVerifier(gens_g, gens_h, u, ComputePInit(), 2).verify_fast(n, _x, _p, challengeGenerator));
};

Expand Down
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