a portable and fast pairing-based cryptography library
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mcl/sample/tri-dh.cpp

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2.3 KiB

/*
tripartie Diffie-Hellman
*/
#include <iostream>
#include <fstream>
#include <cybozu/random_generator.hpp>
#include <mcl/bn256.hpp>
#include <cybozu/option.hpp>
static cybozu::RandomGenerator rg;
const std::string skSuf = ".sk.txt";
const std::string pkSuf = ".pk.txt";
using namespace mcl::bn256;
void keygen(const std::string& user)
{
if (user.empty()) {
throw cybozu::Exception("keygen:user is empty");
}
const char *aa = "12723517038133731887338407189719511622662176727675373276651903807414909099441";
const char *ab = "4168783608814932154536427934509895782246573715297911553964171371032945126671";
const char *ba = "13891744915211034074451795021214165905772212241412891944830863846330766296736";
const char *bb = "7937318970632701341203597196594272556916396164729705624521405069090520231616";
initPairing();
G2 Q(Fp2(aa, ab), Fp2(ba, bb));
G1 P(-1, 1);
Fr s;
s.setRand(rg);
G1::mul(P, P, s);
G2::mul(Q, Q, s);
{
std::string name = user + skSuf;
std::ofstream ofs(name.c_str(), std::ios::binary);
ofs << s << std::endl;
}
{
std::string name = user + pkSuf;
std::ofstream ofs(name.c_str(), std::ios::binary);
ofs << P << std::endl;
ofs << Q << std::endl;
}
}
void load(G1& P, G2& Q, const std::string& fileName)
{
std::ifstream ifs(fileName.c_str(), std::ios::binary);
ifs >> P >> Q;
}
void share(const std::string& skFile, const std::string& pk1File, const std::string& pk2File)
{
initPairing();
Fr s;
G1 P1, P2;
G2 Q1, Q2;
{
std::ifstream ifs(skFile.c_str(), std::ios::binary);
ifs >> s;
}
load(P1, Q1, pk1File);
load(P2, Q2, pk2File);
Fp12 e;
pairing(e, P1, Q2);
{
// verify(not necessary)
Fp12 e2;
pairing(e2, P2, Q1);
if (e != e2) {
throw cybozu::Exception("share:bad public key file") << e << e2;
}
}
Fp12::pow(e, e, s);
std::cout << "share key:\n" << e << std::endl;
}
int main(int argc, char *argv[])
try
{
if (argc == 3 && strcmp(argv[1], "keygen") == 0) {
keygen(argv[2]);
} else if (argc == 5 && strcmp(argv[1], "share") == 0) {
share(argv[2], argv[3], argv[4]);
} else {
fprintf(stderr, "tri-dh.exe keygen <user name>\n");
fprintf(stderr, "tri-dh.exe share <secret key file> <public key1 file> <public key2 file>\n");
return 1;
}
} catch (std::exception& e) {
printf("ERR %s\n", e.what());
return 1;
}