rename inner functions of MapTo

include/mcl/bn.hpp

@@ -576,7 +576,7 @@ struct MapTo {
 	bool calc(G2& P, const Fp2& t, bool fast = false) const
 	{
 		if (mapToMode_ == MCL_MAP_TO_MODE_HASH_TO_CURVE_07) {
-			mapTo_WB19_.opt_swu2_map(P, t);
+			mapTo_WB19_.Fp2ToG2(P, t);
 			return true;
 		}
 		if (!mapToEc(P, t)) return false;

include/mcl/mapto_wb19.hpp

@@ -366,21 +366,17 @@ struct MapTo_WB19 {
 		Fp::neg(y.b, y.b);
 		y.a = t;
 	}
-	bool sgn0(const Fp& x) const
+	bool isNegSign(const Fp& x) const
 	{
 		return x.isOdd();
 	}
-	bool sgn0(const Fp2& x) const
+	bool isNegSign(const Fp2& x) const
 	{
-		bool sign0 = sgn0(x.a);
+		bool sign0 = isNegSign(x.a);
 		bool zero0 = x.a.isZero();
-		bool sign1 = sgn0(x.b);
+		bool sign1 = isNegSign(x.b);
 		return sign0 || (zero0 & sign1);
 	}
-	bool isNegSign(const Fp2& x) const
-	{
-		return sgn0(x);
-	}
 	// https://tools.ietf.org/html/draft-irtf-cfrg-hash-to-curve-07#appendix-D.3.5
 	void sswuG1(Fp& xn, Fp& xd, Fp& y, const Fp& u) const
 	{
@@ -425,7 +421,7 @@ struct MapTo_WB19 {
 			y *= u2;
 			y *= u;
 		}
-		if (sgn0(u) != sgn0(y)) {
+		if (isNegSign(u) != isNegSign(y)) {
 			Fp::neg(y, y);
 		}
 	}
@@ -440,7 +436,7 @@ struct MapTo_WB19 {
 		pt.y *= y;
 	}
 	// https://github.com/algorand/bls_sigs_ref
-	void osswu2_help(E2& P, const Fp2& t) const
+	void sswuG2(E2& P, const Fp2& t) const
 	{
 		Fp2 t2, t2xi;
 		Fp2::sqr(t2, t);
@@ -523,11 +519,6 @@ struct MapTo_WB19 {
 		}
 		assert(0);
 	}
-	void clear_h2(G2& Q, const G2& P) const
-	{
-		// 1.9Mclk can be reduced
-		mcl::local::mulByCofactorBLS12fast(Q, P);
-	}
 	template<class T>
 	void put(const T& P) const
 	{
@@ -536,19 +527,18 @@ struct MapTo_WB19 {
 		printf("y=%s\n", P.y.getStr(base).c_str());
 		printf("z=%s\n", P.z.getStr(base).c_str());
 	}
-	void opt_swu2_map(G2& P, const Fp2& t, const Fp2 *t2 = 0) const
+	void Fp2ToG2(G2& P, const Fp2& t, const Fp2 *t2 = 0) const
 	{
 		E2 Pp;
-		osswu2_help(Pp, t);
+		sswuG2(Pp, t);
 		if (t2) {
 			E2 P2;
-			osswu2_help(P2, *t2);
+			sswuG2(P2, *t2);
 			ec::addJacobi(Pp, Pp, P2);
 		}
 		iso3(P, Pp);
-		clear_h2(P, P);
+		mcl::local::mulByCofactorBLS12fast(P, P);
 	}
-	// hash-to-curve-06
 	void hashToFp2(Fp2 out[2], const void *msg, size_t msgSize, const void *dst, size_t dstSize) const
 	{
 		uint8_t md[256];
@@ -560,16 +550,17 @@ struct MapTo_WB19 {
 			assert(b); (void)b;
 		}
 	}
-	void map2curve_osswu2(G2& out, const void *msg, size_t msgSize, const void *dst, size_t dstSize) const
+	void msgToG2(G2& out, const void *msg, size_t msgSize, const void *dst, size_t dstSize) const
 	{
 		Fp2 t[2];
 		hashToFp2(t, msg, msgSize, dst, dstSize);
-		opt_swu2_map(out, t[0], &t[1]);
+		Fp2ToG2(out, t[0], &t[1]);
 	}
 	void msgToG2(G2& out, const void *msg, size_t msgSize) const
 	{
 		const char *dst = "BLS_SIG_BLS12381G2_XMD:SHA-256_SSWU_RO_POP_";
-		map2curve_osswu2(out, msg, msgSize, dst, strlen(dst));
+		const size_t dstSize = strlen(dst);
+		msgToG2(out, msg, msgSize, dst, dstSize);
 	}
 	void FpToG1(G1& out, const Fp& u0, const Fp *u1 = 0) const
 	{
@@ -595,6 +586,7 @@ struct MapTo_WB19 {
 		}
 		FpToG1(out, u[0], &u[1]);
 	}
+
 	void msgToG1(G1& out, const void *msg, size_t msgSize) const
 	{
 		const char *dst = "BLS_SIG_BLS12381G2_XMD:SHA-256_SSWU_RO_POP_";

include/mcl/op.hpp

@@ -23,7 +23,7 @@
 
 namespace mcl {
 
-static const int version = 0x121; /* 0xABC = A.BC */
+static const int version = 0x122; /* 0xABC = A.BC */
 
 /*
 	specifies available string format mode for X::setIoMode()

readme.md

@@ -315,6 +315,7 @@ If `MCL_USE_OLD_MAPTO_FOR_BLS12` is defined, then the old function is used, but
 
 # History
 
+- 2020/Jun/07 v1.22 remove old hash-to-curve functions
 - 2020/Jun/04 v1.21 mapToG1 and hashAndMapToG1 are compatible to irtf/eip-2537
 - 2020/May/13 v1.09 support draft-irtf-cfrg-hash-to-curve-07
 - 2020/Mar/26 v1.07 change DST for hash-to-curve-06

test/mapto_wb19_test.cpp

@@ -240,7 +240,7 @@ void iso3Test(const T& mapto)
 	mapto.iso3(Q2, P);
 	CYBOZU_TEST_EQUAL(Q1, Q2);
 	set(Q1, clearPs);
-	mapto.clear_h2(Q2, Q2);
+	mcl::local::mulByCofactorBLS12fast(Q2, Q2);
 	CYBOZU_TEST_EQUAL(Q1, Q2);
 }
 
@@ -372,7 +372,7 @@ void testHashToFp2v7(const T& mapto)
 			set(P1.x, tbl[i].x);
 			set(P1.y, tbl[i].y);
 			P1.z = 1;
-			mapto.map2curve_osswu2(P2, msg, msgSize, dst, dstSize);
+			mapto.msgToG2(P2, msg, msgSize, dst, dstSize);
 			CYBOZU_TEST_EQUAL(P1, P2);
 		}
 		{