CertificateID id = new CertificateID(CertificateID.HASH_SHA1, issuerCert, serialNumber);
// basic request generation with nonce
OCSPReqGenerator gen = new OCSPReqGenerator();
gen.addRequest(id);
// create details for nonce extension
Vector<DERObjectIdentifier> oids = new Vector<DERObjectIdentifier>();
Vector<X509Extension> values = new Vector<X509Extension>();