
encryption and authentication is a bad practice.</p>
<p>Because of that, two separate keys are derived from your already configured
<em>encryption_key</em>: one for encryption and one for authentication. This is
done via a technique called <a class="reference external" href="http://en.wikipedia.org/wiki/HKDF">HMAC-based Key Derivation Function</a> (HKDF).</p>
</div>
<div class="section" id="setting-your-encryption-key">
<h3><a class="toc-backref" href="#id5">Setting your encryption_key</a><a class="headerl