How to Extract PGP public key and PGP Private key from JKS File and to Decrypt a pgp Encrypted Message?

I have the following code for decrypting a PGP encrypted Private Key Message.

    KeyStore ks = KeyStore.getInstance("JKS");
    File file = new file("abc.txt");
    ks.load(new FileInputStream("abc.jks"), "******".toCharArray());
    KeyStore.PrivateKeyEntry keyEntry =(KeyStore.PrivateKeyEntry) ks.getEntry("abcd", new KeyStore.PasswordProtection("******".toCharArray()));
    PrivateKey k = keyEntry.getPrivateKey();
    CertificateFactory fact = CertificateFactory.getInstance("X.509");
    FileInputStream is = new FileInputStream ("ght.cer");
    X509Certificate cer = (X509Certificate) fact.generateCertificate(is);
    PublicKey NPCIPubKey = cer.getPublicKey();

    byte[] bt = new byte[(int)file.length()];
    FileInputStream fis = new FileInputStream(file);
    fis.read(bt);
    PGPPublicKey pk1 = new JcaPGPKeyConverter().getPGPPublicKey(PGPPublicKey.RSA_GENERAL, NPCIPubKey, new Date());
    PGPPrivateKey prik = new JcaPGPKeyConverter().getPGPPrivateKey(pk1, k);
    DecClass dec = new DecClass();
    dec.rsaDecryptFile(fis,prik);'

Decryption Class :

public class DecClass {

    public void rsaDecryptFile(InputStream in,  PGPPrivateKey priK)  {
        try {
            Security.addProvider(new BouncyCastleProvider());
            
            in = org.bouncycastle.openpgp.PGPUtil.getDecoderStream(in);
            PGPObjectFactory pgpF = new PGPObjectFactory(in);
            PGPEncryptedDataList enc;
            Object o = pgpF.nextObject();
            //
            // the first object might be a PGP marker packet.
            //
            if (o instanceof PGPEncryptedDataList) {
                enc = (PGPEncryptedDataList) o;
            } else {
                enc = (PGPEncryptedDataList) pgpF.nextObject();
            }                        

                        Iterator<PGPPublicKeyEncryptedData> it = enc.getEncryptedDataObjects();
            PGPPrivateKey sKey = null;
            PGPPublicKeyEncryptedData pbe = null;

            while (sKey == null && it.hasNext()) {
                pbe = it.next();
                sKey = priK;
            }

            if (sKey == null) {
                throw new IllegalArgumentException("Secret key for message not found.");
            }
            
            PublicKeyDataDecryptorFactory b = new JcePublicKeyDataDecryptorFactoryBuilder().setProvider("BC")
                    .setContentProvider("BC").build(sKey);

            InputStream clear = pbe.getDataStream(b);
            PGPObjectFactory plainFact = new PGPObjectFactory(clear,new BcKeyFingerprintCalculator());

            Object message = plainFact.nextObject();
            System.out.println("Secret key info 3:: " + pbe.getKeyID() + new Date());
            if (message instanceof PGPCompressedData) {
                PGPCompressedData cData = (PGPCompressedData) message;
                PGPObjectFactory pgpFact = new PGPObjectFactory(cData.getDataStream(),new BcKeyFingerprintCalculator());
                message = pgpFact.nextObject();
            }           
            if (message instanceof PGPLiteralData) {
                PGPLiteralData ld = (PGPLiteralData) message;
                InputStream unc = ld.getInputStream();
                int ch;             
                FileUtils.copyInputStreamToFile(unc, new File("D:\\Development_Docs\\PGP\\Bulk\\target.txt"));
                
            } else if (message instanceof PGPOnePassSignatureList) {
                throw new PGPException("Encrypted message contains a signed message - not literal data.");
            } else {
                throw new PGPException("Message is not a simple encrypted file - type unknown.");
            }if (pbe.isIntegrityProtected()) {
                if (!pbe.verify()) {
                    throw new PGPException("Message failed integrity check");
                }
            }           
        }catch (PGPException e) {
            e.printStackTrace();
        }catch (Exception e) {
            e.printStackTrace();
        }   
    }
}

But am getting null pointer exception in Iterator<PGPPublicKeyEncryptedData> it = enc.getEncryptedDataObjects(); line in DecClass rsaDecryptFile Method.While debugging value of PGPEncryptedDataList enc is coming null. Am not able to trace the source of the exception. Please advise on how can i resolve this exception and get the code to work. Please find below snippet of my input encrypted message

Solution

I'm able to decrypt the file by modifing the following code.Hope it'll work for you.

        @SuppressWarnings({ "unchecked", "unused" })
        public static void rsaDecryptFile(InputStream in, OutputStream out, 
        PGPPrivateKey priK)  {
    try {
        Security.addProvider(new BouncyCastleProvider());
        
        in = org.bouncycastle.openpgp.PGPUtil.getDecoderStream(in);
        PGPObjectFactory pgpF = new PGPObjectFactory(in,new 
        JcaKeyFingerprintCalculator());
        PGPEncryptedDataList enc;
        Object o = pgpF.nextObject();
        //
        // the first object might be a PGP marker packet.
        //
        if (o instanceof PGPEncryptedDataList) {
            enc = (PGPEncryptedDataList) o;
        } else {
            enc = (PGPEncryptedDataList) pgpF.nextObject();
        }

        //
        // find the secret key
        //
        //Iterator<PGPPublicKeyEncryptedData> it = enc.getEncryptedDataObjects();
        PGPPrivateKey sKey = null;
        PGPPublicKeyEncryptedData pbe = null;

        while (sKey == null /*&& it.hasNext()*/) {
            //pbe = it.next();
            pbe = (PGPPublicKeyEncryptedData)enc.getEncryptedDataObjects().next();
            //sKey = findSecretKey(pubK, pbe.getKeyID(), priK);
            sKey = priK;
            

        }

        if (sKey == null) throw new IllegalArgumentException("Secret key for message not found.");
        
        PublicKeyDataDecryptorFactory b = new JcePublicKeyDataDecryptorFactoryBuilder().setProvider("BC")
                .setContentProvider("BC").build(sKey);

        InputStream clear = pbe.getDataStream(b);
        PGPObjectFactory plainFact = new PGPObjectFactory(clear,new JcaKeyFingerprintCalculator());

        Object message = plainFact.nextObject();
        System.out.println("Secret key info 3:: " + pbe.getKeyID() + new Date());
        if (message instanceof PGPCompressedData) {
            PGPCompressedData cData = (PGPCompressedData) message;
            PGPObjectFactory pgpFact = new PGPObjectFactory(cData.getDataStream(),new JcaKeyFingerprintCalculator());

            message = pgpFact.nextObject();
        }
        
        if (message instanceof PGPLiteralData) {
            PGPLiteralData ld = (PGPLiteralData) message;
            InputStream unc = ld.getInputStream();
            System.out.println("Unc d " + unc.read());
            int ch;
            
            while ((ch = unc.read()) >= 0) { 
                out.write(ch); 
                }
             
             

            //FileUtils.copyInputStreamToFile(unc, new File("D:\\Development_Docs\\PGP\\Bulk\\target.txt"));

            
        } else if (message instanceof PGPOnePassSignatureList) {
            throw new PGPException("Encrypted message contains a signed message - not literal data.");
        } else {
            throw new PGPException("Message is not a simple encrypted file - type unknown.");
        }
        

        if (pbe.isIntegrityProtected()) {
            if (!pbe.verify()) {
                throw new PGPException("Message failed integrity check");
            }
        }
        
        
    }catch (PGPException e) {
        // TODO: handle exception
        e.printStackTrace();
    }catch (Exception e) {
        // TODO: handle exception
        e.printStackTrace();
    }
    
    
}