ss="field-body"><ul class="first simple">
<li><strong>$key</strong> (<em>string</em>) – Input key material</li>
<li><strong>$digest</strong> (<em>string</em>) – A SHA-2 family digest algorithm</li>
<li><strong>$salt</strong> (<em>string</em>) – Optional salt</li>
<li><strong>$length</strong> (<em>int</em>) – Optional output length</li>
<li><strong>$info</strong> (<em>string</em>) – Optional context/application-specific info</li>
</ul>
</td>
</tr>
<tr class="field-even field"><th class="field-name"