tripartie diffie-hellman sample

1 files changed, 110 insertions, 0 deletions

diff --git a/sample/tri-dh.cpp b/sample/tri-dh.cpp
new file mode 100644
index 0000000..0ff28f5
--- /dev/null
+++ b/sample/tri-dh.cpp
@@ -0,0 +1,110 @@
+/*
+	tripartie Diffie-Hellman
+*/
+#include <iostream>
+#include <fstream>
+#include <cybozu/random_generator.hpp>
+#include <mcl/bn.hpp>
+#include <cybozu/option.hpp>
+
+typedef mcl::FpT<mcl::FpTag, 256> Fp;
+typedef mcl::bn::BNT<Fp> BN;
+typedef BN::Fp2 Fp2;
+typedef BN::Fp12 Fp12;
+typedef BN::G1 G1;
+typedef BN::G2 G2;
+
+struct FrTag;
+typedef mcl::FpT<FrTag, 256> Fr;
+
+static cybozu::RandomGenerator rg;
+
+const std::string skSuf = ".sk.txt";
+const std::string pkSuf = ".pk.txt";
+
+void setup()
+{
+	BN::init();
+	Fr::init(BN::param.r);
+}
+
+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";
+
+	setup();
+	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)
+{
+	setup();
+	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;
+	BN::pairing(e, Q2, P1);
+	{
+		// verify(not necessary)
+		Fp12 e2;
+		BN::pairing(e2, Q1, P2);
+		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;
+}
+