Security.addProvider(new org.bouncycastle.jce.provider.BouncyCastleProvider());
// Generate the id for the certificate we are looking for
CertificateID id = new CertificateID(
new JcaDigestCalculatorProviderBuilder().build().get(CertificateID.HASH_SHA1),
new JcaX509CertificateHolder(issuerCert), serialNumber);
// basic request generation with nonce
OCSPReqBuilder gen = new OCSPReqBuilder();
gen.addRequest(id);