List<KeyResolver> keyResolverList = new ArrayList<KeyResolver>();
keyResolverList.add(new KeyResolver(new RSAKeyValueResolver()));
keyResolverList.add(new KeyResolver(new DSAKeyValueResolver()));
keyResolverList.add(new KeyResolver(new X509CertificateResolver()));
keyResolverList.add(new KeyResolver(new X509SKIResolver()));
keyResolverList.add(new KeyResolver(new RetrievalMethodResolver()));
keyResolverList.add(new KeyResolver(new X509SubjectNameResolver()));
keyResolverList.add(new KeyResolver(new X509IssuerSerialResolver()));
keyResolverList.add(new KeyResolver(new DEREncodedKeyValueResolver()));
keyResolverList.add(new KeyResolver(new KeyInfoReferenceResolver()));
keyResolverList.add(new KeyResolver(new X509DigestResolver()));