 and are being used.</p>

<pre><code>           +--------------------+
           | os entropy sources |
           +--------------------+
                    |
                    v           +-----------------------------+
 RAND_add() ==&gt; &lt;primary&gt;     &lt;-| shared DRBG (with locking)  |
                  /   \         +-----------------------------+
                 /     \              +---------------------------+
          &lt;public&gt;     &lt;private&gt;   &lt;- | per-thread DRBG instance