return C._goboringcrypto_BN_bin2bn((*C.uint8_t)(&x[0]), C.size_t(len(x)), nil)
}

func bnToBig(bn *C.GO_BIGNUM) BigInt {
	x := make(BigInt, (C._goboringcrypto_BN_num_bytes(bn)+wordBytes-1)/wordBytes)
	if C._goboringcrypto_BN_bn2le_padded(wbase(x), C.size_t(len(x)*wordBytes), bn) == 0 {
		panic("boringcrypto: bignum conversion failed")
	}
	return x
}

func bigToBn(bnp **C.GO_BIGNUM, b BigInt) bool {
	if *bnp != nil {

GO_BIGNUM* _goboringcrypto_BN_bin2bn(const uint8_t*, size_t, GO_BIGNUM*);
GO_BIGNUM* _goboringcrypto_BN_le2bn(const uint8_t*, size_t, GO_BIGNUM*);
size_t _goboringcrypto_BN_bn2bin(const GO_BIGNUM*, uint8_t*);
int _goboringcrypto_BN_bn2le_padded(uint8_t*, size_t, const GO_BIGNUM*);
int _goboringcrypto_BN_bn2bin_padded(uint8_t*, size_t, const GO_BIGNUM*);

// #include <openssl/ec.h>