protected CertPathParameters getParameters(String algorithm, String crlf, KeyStore trustStore) throws Exception {
CertPathParameters params;
if ("PKIX".equalsIgnoreCase(algorithm)) {
PKIXBuilderParameters xparams = new PKIXBuilderParameters(trustStore, new X509CertSelector());
Collection crls = getCRLs(crlf);
CertStoreParameters csp = new CollectionCertStoreParameters(crls);
CertStore store = CertStore.getInstance("Collection", csp);
xparams.addCertStore(store);
xparams.setRevocationEnabled(true);
String trustLength = (String) attributes.get("trustMaxCertLength");
if (trustLength != null) {