if (! input.isElement())
throw new NotImplementedException("Only element input is supported");
// Resolve the BinarySecurityToken associated with this SecurityTokenReference
Element element = (Element)input.getSubNode();
SecurityTokenReference ref = new SecurityTokenReference(element);
KeyResolver resolver = new KeyResolver(store);
BinarySecurityToken token = resolver.resolve(ref);
// Get the specially formated dom element for this element
element = token.getSTRTransformElement();