<a href="//commons.wikimedia.org/wiki/File:Cascade-protection-shackle.svg" title="File:Cascade-protection-shackle.svg">Cascade-protection-shackle.svg</a> with a keyhole on the lock instead of an icon.
<a href="//commons.wikimedia.org/wiki/User:Mifter" title="User:Mifter">Mifter</a>
Own work based on: <a href="//commons.wikimedia.org/wiki/File:Cascade-protection-shackle.svg" title="File:Cascade-protection-shackle.svg">Cascade-protection-shackle.svg</a> <i>by</i> <a href="//commons.wikimedia.org/wiki/User:XYZtSpace" class="mw-redirect" title="User:XYZtSpace">XYZtSpace</a>