title: How to store encryption key in safe (C++)?
body: <p>I want to use <a href="https://github.com/xxtea/xxtea-c" rel="nofollow">xxtea</a> for data encryption/decryption in my game.</p>
  
  <p>Here is the example of library usage:</p>
  
  <pre><code>#include &lt;stdio.h&gt;
  #include &lt;string.h&gt;
  #include &lt;xxtea.h&gt;
  
  int main() {
      const char *text = "Hello World! 你好，中国！";
      const char *key = "1234567890";
      size_t len;
      unsigned char *encrypt_data = xxtea_encrypt(text, strlen(text), key, &amp;len);
      char *decrypt_data = xxtea_decrypt(encrypt_data, len, key, &amp;len);
      if (strncmp(text, decrypt_data, len) == 0) {
          printf("success!\n");
      }
      else {
          printf("fail!\n");
      }
      free(encrypt_data);
      free(decrypt_data);
      return 0;
  }
  </code></pre>
  
  <p>How to keep the key itself in safe then?</p>