Getting pgp keys and making thenm json

pgpToJson.php

<?php

$results = file_get_contents('http://gpg.mozilla.org/pks/lookup?search=jfinstrom&op=index');
$dom = new DOMDocument;
$dom->loadHTML($results);
$keys = [];
foreach($dom->getElementsByTagName('a') as $link) {
        $key = substr($link->getAttribute('href'), -18);
        $value = $link->textContent;
        $keys[$key] = $value;
}
echo json_encode($keys);