std::string toHexString(bool number) { return (number ? toHexString("1") : toHexString("0")); }
int signMessageWithPem(char *message, char *pem, char **signature) {
unsigned int meslen = strlen(message);
unsigned char *messagebytes = calloc(meslen, sizeof(unsigned char));
int derSigLen = 0;
int i = 0;
memcpy(messagebytes, message, meslen);
EC_KEY *key = NULL;
BIO *in = NULL;
unsigned char *buffer = NULL;
char *sha256ofMsg = calloc(SHA256_HEX_STRING, sizeof(char));
unsigned char *outBytesOfsha256ofMsg = calloc(SHA256_STRING, sizeof(unsigned char));
digestOfBytes(messagebytes, &sha256ofMsg, "sha256", meslen);
sha256ofMsg[64] = '\0';
createDataWithHexString(sha256ofMsg, &outBytesOfsha256ofMsg);
in = BIO_new(BIO_s_mem());
BIO_puts(in, pem);
key = PEM_read_bio_ECPrivateKey(in, NULL, NULL, NULL);
if(key == NULL) {
return ERROR;
}
while(derSigLen < 70 && i < 10) {
i++;
ECDSA_SIG *sig = ECDSA_do_sign((const unsigned char*)outBytesOfsha256ofMsg, SHA256_DIGEST_LENGTH, key);
int verify = ECDSA_do_verify((const unsigned char*)outBytesOfsha256ofMsg, SHA256_DIGEST_LENGTH, sig, key);
if(verify != 1) {
return ERROR;
}
int buflen = ECDSA_size(key);
buffer = OPENSSL_malloc(buflen);
derSigLen = i2d_ECDSA_SIG(sig, &buffer);
}
if(i == 10)
return ERROR;
char *hexData = calloc(derSigLen, sizeof(char));
memcpy(hexData, buffer-derSigLen, derSigLen);
char *hexString = calloc(derSigLen*2+1, sizeof(char));
toHexString(hexData, derSigLen, &hexString);
hexString[derSigLen * 2] = '\0';
memcpy(*signature, hexString, (derSigLen*2)+ 1);
EC_KEY_free(key);
BIO_free_all(in);
free(messagebytes);
free(sha256ofMsg);
free(outBytesOfsha256ofMsg);
free(hexData);
free(hexString);
return NOERROR;
}
