if (this._storageResolvers.size() == 0) {
// if we do not have storage resolvers, we verify with null
StorageResolver storage = null;
if (keyResolver.engineCanResolve((Element) currentChild,
this.getBaseURI(),
storage)) {
X509Certificate cert =
keyResolver.engineResolveX509Certificate(
(Element) currentChild, this.getBaseURI(), storage);