PGPObjectFactory pgpFact = new PGPObjectFactory(aIn);
PGPSignatureList p3 = (PGPSignatureList)pgpFact.nextObject();
PGPSignature sig = p3.get(0);
PGPPublicKey publicKey = pgpRings.getPublicKey(sig.getKeyID());
sig.init(new JcaPGPContentVerifierBuilderProvider().setProvider("BC"), publicKey);
//
// read the input, making sure we ignore the last newline.
//