break backword compatibility of 2nd argument of mclBn_init

ffi/go/mcl/mcl.go

@@ -32,7 +32,7 @@ const IoSerializeHexStr = C.MCLBN_IO_SERIALIZE_HEX_STR
 // call this function before calling all the other operations
 // this function is not thread safe
 func Init(curve int) error {
-	err := C.mclBn_init(C.int(curve), C.MCLBN_FP_UNIT_SIZE)
+	err := C.mclBn_init(C.int(curve), C.MCLBN_COMPILED_TIME_VAR)
 	if err != 0 {
 		return fmt.Errorf("ERR mclBn_init curve=%d", curve)
 	}

include/mcl/bn.h

@@ -6,9 +6,16 @@
 	@license modified new BSD license
 	http://opensource.org/licenses/BSD-3-Clause
 */
+/*
+	the order of an elliptic curve over Fp is Fr
+*/
 #ifndef MCLBN_FP_UNIT_SIZE
 	#error "define MCLBN_FP_UNIT_SIZE 4(, 6 or 8)"
 #endif
+#ifndef MCLBN_FR_UNIT_SIZE
+	#define MCLBN_FR_UNIT_SIZE MCLBN_FP_UNIT_SIZE
+#endif
+#define MCLBN_COMPILED_TIME_VAR ((MCLBN_FR_UNIT_SIZE) * 10 + (MCLBN_FP_UNIT_SIZE))
 
 #include <stdint.h> // for uint64_t, uint8_t
 #include <stdlib.h> // for size_t
@@ -65,7 +72,7 @@ typedef struct mclBnGT mclBnGT;
 #else
 
 typedef struct {
-	uint64_t d[MCLBN_FP_UNIT_SIZE];
+	uint64_t d[MCLBN_FR_UNIT_SIZE];
 } mclBnFr;
 
 typedef struct {
@@ -98,15 +105,17 @@ enum {
 /*
 	init library
 	@param curve [in] type of bn curve
-	@param maxUnitSize [in] MCLBN_FP_UNIT_SIZE
-	return 0 if success else -1
+	@param compiledTimeVar [in] specify MCLBN_COMPILED_TIME_VAR,
+	which macro is used to make sure that the values
+	are the same when the library is built and used
+	@return 0 if success
 	curve = BN254/BN_SNARK1 is allowed if maxUnitSize = 4
 	curve = BN381_1/BN381_2/BLS12_381 are allowed if maxUnitSize = 6
 	This parameter is used to detect a library compiled with different MCLBN_FP_UNIT_SIZE for safety.
 	@note not threadsafe
 	@note BN_init is used in libeay32
 */
-MCLBN_DLL_API int mclBn_init(int curve, int maxUnitSize);
+MCLBN_DLL_API int mclBn_init(int curve, int compiledTimeVar);
 
 
 /*

include/mcl/she.h

@@ -78,12 +78,14 @@ typedef struct {
 	initialize this library
 	call this once before using the other functions
 	@param curve [in] enum value defined in mcl/bn.h
-	@param maxUnitSize [in] MCLBN_FP_UNIT_SIZE (fixed)
-	return 0 if success
+	@param compiledTimeVar [in] specify MCLBN_COMPILED_TIME_VAR,
+	which macro is used to make sure that the values
+	are the same when the library is built and used
+	@return 0 if success
 	@note sheInit() is thread safe and serialized if it is called simultaneously
 	but don't call it while using other functions.
 */
-MCLSHE_DLL_API int sheInit(int curve, int maxUnitSize);
+MCLSHE_DLL_API int sheInit(int curve, int compiledTimeVar);
 
 // return written byte size if success else 0
 MCLSHE_DLL_API mclSize sheSecretKeySerialize(void *buf, mclSize maxBufSize, const sheSecretKey *sec);

readme.md

@@ -10,6 +10,7 @@ mcl is a library for pairing-based cryptography.
 The current version supports the optimal Ate pairing over BN curves and BLS12-381 curves.
 
 # News
+* 2nd argument of `mclBn_init` is changed from `maxUnitSize` to `compiledTimeVar`, which must be `MCLBN_COMPILED_TIME_VAR`.
 * break backward compatibility of mapToGi for BLS12. A map-to-function for BN is used.
 If `MCL_USE_OLD_MAPTO_FOR_BLS12` is defined, then the old function is used, but this will be removed in the future.
 

src/bn_c_impl.hpp

@@ -45,9 +45,9 @@ extern "C" MCLBN_DLL_API void mclBnFree(void *p)
 }
 #endif
 
-int mclBn_init(int curve, int maxUnitSize)
+int mclBn_init(int curve, int compiledTimeVar)
 {
-	if (maxUnitSize != MCLBN_FP_UNIT_SIZE) {
+	if (compiledTimeVar != MCLBN_COMPILED_TIME_VAR) {
 		return -10;
 	}
 	const mcl::CurveParam& cp = mcl::getCurveParam(curve);

src/she_c_impl.hpp

@@ -41,10 +41,10 @@ static const ZkpEq *cast(const sheZkpEq *p) { return reinterpret_cast<const ZkpE
 static ZkpBinEq *cast(sheZkpBinEq *p) { return reinterpret_cast<ZkpBinEq*>(p); }
 static const ZkpBinEq *cast(const sheZkpBinEq *p) { return reinterpret_cast<const ZkpBinEq*>(p); }
 
-int sheInit(int curve, int maxUnitSize)
+int sheInit(int curve, int compiledTimeVar)
 	try
 {
-	if (maxUnitSize != MCLBN_FP_UNIT_SIZE) {
+	if (compiledTimeVar != MCLBN_COMPILED_TIME_VAR) {
 		return -2;
 	}
 	mcl::CurveParam cp;

test/bn_c_test.hpp

@@ -26,13 +26,13 @@ CYBOZU_TEST_AUTO(init)
 
 #if MCLBN_FP_UNIT_SIZE == 4
 	printf("test BN254 %d\n", MCLBN_FP_UNIT_SIZE);
-	ret = mclBn_init(MCL_BN254, MCLBN_FP_UNIT_SIZE);
+	ret = mclBn_init(MCL_BN254, MCLBN_COMPILED_TIME_VAR);
 #elif MCLBN_FP_UNIT_SIZE == 6
 	printf("test BN381_1 %d\n", MCLBN_FP_UNIT_SIZE);
-	ret = mclBn_init(MCL_BN381_1, MCLBN_FP_UNIT_SIZE);
+	ret = mclBn_init(MCL_BN381_1, MCLBN_COMPILED_TIME_VAR);
 #elif MCLBN_FP_UNIT_SIZE == 8
 	printf("test BN462 %d\n", MCLBN_FP_UNIT_SIZE);
-	ret = mclBn_init(MCL_BN462, MCLBN_FP_UNIT_SIZE);
+	ret = mclBn_init(MCL_BN462, MCLBN_COMPILED_TIME_VAR);
 #else
 	#error "bad MCLBN_FP_UNIT_SIZE"
 #endif
@@ -508,7 +508,7 @@ CYBOZU_TEST_AUTO(serializeToHexStr)
 CYBOZU_TEST_AUTO(badG2)
 {
 	int ret;
-	ret = mclBn_init(MCL_BN381_1, MCLBN_FP_UNIT_SIZE);
+	ret = mclBn_init(MCL_BN381_1, MCLBN_COMPILED_TIME_VAR);
 	CYBOZU_TEST_EQUAL(ret, 0);
 	const char *s = "1 18d3d8c085a5a5e7553c3a4eb628e88b8465bf4de2612e35a0a4eb018fb0c82e9698896031e62fd7633ffd824a859474 1dc6edfcf33e29575d4791faed8e7203832217423bf7f7fbf1f6b36625b12e7132c15fbc15562ce93362a322fb83dd0d 65836963b1f7b6959030ddfa15ab38ce056097e91dedffd996c1808624fa7e2644a77be606290aa555cda8481cfb3cb 1b77b708d3d4f65aeedf54b58393463a42f0dc5856baadb5ce608036baeca398c5d9e6b169473a8838098fd72fd28b50";
 	mclBnG2 Q;