Instead of accessing a single DRBG instance concurrently from different threads, it is recommended to instantiate a separate DRBG instance per thread. Using the &lt;primary&gt; DRBG as entropy source for multiple DRBG instances on different threads is thread-safe, because the DRBG instance will lock the &lt;primary&gt; DRBG automatically for obtaining random input.</p>

<h1 id="THE-OVERALL-PICTURE">THE OVERALL PICTURE</h1>

<p>The following picture gives an overview over how the DRBG instances work together