ing-certificate-and-key">Plugging in the existing certificate and key</h2><p>Suppose we want to have Istio CA use the existing certificate <code class="highlighter-rouge">ca-cert.pem</code> and key <code class="highlighter-rouge">ca-key.pem</code>. Furthermore, the certificate <code class="highlighter-rouge">ca-cert.pem</code> is signed by the root certificate <code class="highlighter-rouge">root-cert.pem</code>, and we would like to use <code class="highlighter-rouge">root-cert.pem</code> as the root certi