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gittivergittiver
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added test_crypto.cpp with first code for rsa blinding
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3 files changed

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3 files changed

+259
-2
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‎CMakeLists.txt‎

Lines changed: 6 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -18,6 +18,8 @@ else()
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endif()
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set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
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include(FetchContent)
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#
@@ -99,7 +101,10 @@ add_executable(${PROJECT_NAME} src/main.cpp)
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target_link_libraries(${PROJECT_NAME} PRIVATE oc-mint-lib INTERFACE tl::expected::expected)
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## these are unittests that can be run on any platform
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add_executable(tests test/test_big_int.cpp test/test.cpp)
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add_executable(tests test/test_big_int.cpp
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test/test_json_s8n.cpp
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test/test_crypto.cpp)
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target_link_libraries(tests
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oc-mint-lib
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Catch2::Catch2WithMain)

‎test/test_crypto.cpp‎

Lines changed: 252 additions & 0 deletions
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@@ -0,0 +1,252 @@
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#include <catch2/catch_test_macros.hpp>
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#include "cryptlib.h"
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#include "integer.h"
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#include "nbtheory.h"
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#include "osrng.h"
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#include "rsa.h"
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#include "sha.h"
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#include <iostream>
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#include <stdexcept>
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CryptoPP::Integer blind_signature(const CryptoPP::SecByteBlock& orig,
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CryptoPP::Integer& r,
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const CryptoPP::RSA::PublicKey& pub_key,
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const CryptoPP::RSA::PrivateKey& priv_key) {
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using namespace CryptoPP;
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using std::cout;
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using std::endl;
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// Convenience
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const Integer &n = pub_key.GetModulus();
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const Integer &e = pub_key.GetPublicExponent();
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const Integer &d = priv_key.GetPrivateExponent();
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// For sizing the hashed message buffer. This should be SHA256 size.
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const size_t sig_size = UnsignedMin(SHA256::BLOCKSIZE, n.ByteCount());
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// Scratch
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SecByteBlock buff_1, buff_2, buff_3;
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Integer m(orig.data(), orig.size());
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cout << "Message: " << std::hex << m << endl;
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// Hash message per Rabin (1979)
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buff_1.resize(sig_size);
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SHA256 hash_1;
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hash_1.CalculateTruncatedDigest(buff_1, buff_1.size(), orig, orig.size());
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// H(m) as Integer
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Integer hm(buff_1.data(), buff_1.size());
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cout << "H(m): " << std::hex << hm << endl;
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// Blinding factor
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Integer b = a_exp_b_mod_c(r, e, n);
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cout << "Random: " << std::hex << b << endl;
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// Alice blinded message
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Integer mm = a_times_b_mod_c(hm, b, n);
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cout << "Blind msg: " << std::hex << mm << endl;
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AutoSeededRandomPool prng;
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// Bob sign
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Integer ss = priv_key.CalculateInverse(prng, mm);
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cout << "Blind sign: " << ss << endl;
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return ss;
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}
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CryptoPP::Integer unblind_signature(CryptoPP::Integer const & ss,
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CryptoPP::Integer& r,
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const CryptoPP::RSA::PublicKey& pub_key)
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{
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const CryptoPP::Integer &n = pub_key.GetModulus();
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CryptoPP::Integer s = a_times_b_mod_c(ss, r.InverseMod(n), n);
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return s;
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}
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CryptoPP::Integer verify(CryptoPP::Integer const & ss,
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CryptoPP::Integer& r,
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const CryptoPP::RSA::PublicKey& pub_key)
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{
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CryptoPP::Integer s = unblind_signature(ss,r,pub_key);
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CryptoPP::Integer v = pub_key.ApplyFunction(s);
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return v;
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}
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TEST_CASE("cryptopp1", "[crypto]") {
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using namespace CryptoPP;
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using std::cout;
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using std::endl;
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using std::runtime_error;
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// Bob artificially small key pair
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AutoSeededRandomPool prng;
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RSA::PrivateKey priv_key;
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priv_key.GenerateRandomWithKeySize(prng, 64U);
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RSA::PublicKey pub_key(priv_key);
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// Convenience
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const Integer &n = pub_key.GetModulus();
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const Integer &e = pub_key.GetPublicExponent();
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const Integer &d = priv_key.GetPrivateExponent();
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// Print params
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cout << "Pub mod: " << std::hex << pub_key.GetModulus() << endl;
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cout << "Pub exp: " << std::hex << e << endl;
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cout << "Priv mod: " << std::hex << priv_key.GetModulus() << endl;
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cout << "Priv exp: " << std::hex << d << endl;
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const char* MESSAGE = "secret";
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SecByteBlock orig((const byte *)MESSAGE, 6U);
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// Alice blinding
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Integer r;
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do {
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r.Randomize(prng, Integer::One(), n - Integer::One());
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} while (!RelativelyPrime(r, n));
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CryptoPP::Integer ss = blind_signature(orig,
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r,
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pub_key,
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priv_key);
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// Alice checks s(s'(x)) = x. This is from Chaum's paper
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Integer c = pub_key.ApplyFunction(ss);
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cout << "Check sign: " << c << endl;
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//if (c != mm) {
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// throw runtime_error("Alice cross-check failed");
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// }
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// Alice remove blinding
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Integer s = unblind_signature(ss, r, pub_key);
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cout << "Unblind sign: " << s << endl;
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// Eve verifies
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Integer v = verify(ss, r, pub_key);
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cout << "Verify: " << std::hex << v << endl;
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// Scratch
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SecByteBlock buff_2, buff_3;
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// Convert to a string
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size_t req = v.MinEncodedSize();
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buff_2.resize(req);
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v.Encode(&buff_2[0], buff_2.size());
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// Hash message per Rabin (1979)
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const size_t sig_size = UnsignedMin(SHA256::BLOCKSIZE, n.ByteCount());
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buff_3.resize(sig_size);
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SHA256 hash_2;
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hash_2.CalculateTruncatedDigest(buff_3, buff_3.size(), orig, orig.size());
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// Constant time compare
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bool equal = buff_2.size() == buff_3.size() &&
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VerifyBufsEqual(buff_2.data(), buff_3.data(), buff_3.size());
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if (!equal) {
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throw runtime_error("Eve verified failed");
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}
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cout << "Verified signature" << endl;
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}
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TEST_CASE("cryptopp", "[crypto]") {
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using namespace CryptoPP;
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using std::cout;
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using std::endl;
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using std::runtime_error;
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// Bob artificially small key pair
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AutoSeededRandomPool prng;
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RSA::PrivateKey priv_key;
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priv_key.GenerateRandomWithKeySize(prng, 64U);
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RSA::PublicKey pub_key(priv_key);
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// Convenience
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const Integer &n = pub_key.GetModulus();
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const Integer &e = pub_key.GetPublicExponent();
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const Integer &d = priv_key.GetPrivateExponent();
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// Print params
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cout << "Pub mod: " << std::hex << pub_key.GetModulus() << endl;
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cout << "Pub exp: " << std::hex << e << endl;
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cout << "Priv mod: " << std::hex << priv_key.GetModulus() << endl;
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cout << "Priv exp: " << std::hex << d << endl;
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// For sizing the hashed message buffer. This should be SHA256 size.
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const size_t sig_size = UnsignedMin(SHA256::BLOCKSIZE, n.ByteCount());
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// Scratch
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SecByteBlock buff_1, buff_2, buff_3;
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// Alice original message to be signed by Bob
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SecByteBlock orig((const byte *)"secret", 6U);
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Integer m(orig.data(), orig.size());
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cout << "Message: " << std::hex << m << endl;
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// Hash message per Rabin (1979)
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buff_1.resize(sig_size);
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SHA256 hash_1;
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hash_1.CalculateTruncatedDigest(buff_1, buff_1.size(), orig, orig.size());
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// H(m) as Integer
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Integer hm(buff_1.data(), buff_1.size());
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cout << "H(m): " << std::hex << hm << endl;
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// Alice blinding
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Integer r;
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do {
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r.Randomize(prng, Integer::One(), n - Integer::One());
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} while (!RelativelyPrime(r, n));
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// Blinding factor
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Integer b = a_exp_b_mod_c(r, e, n);
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cout << "Random: " << std::hex << b << endl;
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// Alice blinded message
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Integer mm = a_times_b_mod_c(hm, b, n);
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cout << "Blind msg: " << std::hex << mm << endl;
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// Bob sign
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Integer ss = priv_key.CalculateInverse(prng, mm);
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cout << "Blind sign: " << ss << endl;
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// Alice checks s(s'(x)) = x. This is from Chaum's paper
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Integer c = pub_key.ApplyFunction(ss);
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cout << "Check sign: " << c << endl;
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if (c != mm) {
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throw runtime_error("Alice cross-check failed");
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}
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// Alice remove blinding
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Integer s = a_times_b_mod_c(ss, r.InverseMod(n), n);
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cout << "Unblind sign: " << s << endl;
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// Eve verifies
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Integer v = pub_key.ApplyFunction(s);
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cout << "Verify: " << std::hex << v << endl;
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// Convert to a string
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size_t req = v.MinEncodedSize();
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buff_2.resize(req);
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v.Encode(&buff_2[0], buff_2.size());
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// Hash message per Rabin (1979)
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buff_3.resize(sig_size);
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SHA256 hash_2;
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hash_2.CalculateTruncatedDigest(buff_3, buff_3.size(), orig, orig.size());
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// Constant time compare
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bool equal = buff_2.size() == buff_3.size() &&
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VerifyBufsEqual(buff_2.data(), buff_3.data(), buff_3.size());
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if (!equal) {
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throw runtime_error("Eve verified failed");
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}
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cout << "Verified signature" << endl;
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}

‎test/test.cpp‎ renamed to ‎test/test_json_s8n.cpp‎

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -12,7 +12,7 @@ TEST_CASE( "PublicKey::to_json", "[to_json]" ) {
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REQUIRE( json["modulus"].dump() == "\"" + k.modulus.to_string() + "\"" );
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REQUIRE( json["public_exponent"].dump() == "\"" + k.public_exponent.to_string()+"\"" );
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REQUIRE( json["type"].dump() == "\"rsa public key\"" );
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REQUIRE( json.keys().size() == 3 );
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REQUIRE( json.keys().size() == 3U );
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}
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TEST_CASE("RequestCDDCSerial::from_string", "[from_string]") {

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