void WideToAnsi( const std::wstring & ws, std::string & s ) {
    char str[500];
    WideCharToMultiByte( CP_UTF8, 0, ws.c_str(), -1, str, 500, 0, 0);
    s = str;
}
//.....
        DWORD outSize = 0;
        if (CryptBinaryToString(certCtx->pCertInfo->SerialNumber.pbData, certCtx->pCertInfo->SerialNumber.cbData, CRYPT_STRING_HEX | CRYPT_STRING_NOCRLF, NULL, &outSize)) {
            std::wstring serial;
            serial.resize(outSize);
            if (CryptBinaryToString(certCtx->pCertInfo->SerialNumber.pbData, certCtx->pCertInfo->SerialNumber.cbData, CRYPT_STRING_HEX | CRYPT_STRING_NOCRLF, &(serial[0]), &outSize)) {
                WideToAnsi(serial, cert->SerialNumber);
                cert->SerialNumber = "0x" + cert->SerialNumber;
            }
        }