PgpHelper.java

package info.guardianproject.iocipher.camera.io;

import org.jcodec.common.IOUtils;
import org.spongycastle.bcpg.ArmoredOutputStream;
import org.spongycastle.jce.provider.BouncyCastleProvider;
import org.spongycastle.openpgp.*;
import org.spongycastle.openpgp.operator.PBESecretKeyDecryptor;
import org.spongycastle.openpgp.operator.PublicKeyDataDecryptorFactory;
import org.spongycastle.openpgp.operator.bc.BcPGPDataEncryptorBuilder;
import org.spongycastle.openpgp.operator.jcajce.JcaPGPDigestCalculatorProviderBuilder;
import org.spongycastle.openpgp.operator.jcajce.JcePBESecretKeyDecryptorBuilder;
import org.spongycastle.openpgp.operator.jcajce.JcePGPDataEncryptorBuilder;
import org.spongycastle.openpgp.operator.jcajce.JcePublicKeyDataDecryptorFactoryBuilder;
import org.spongycastle.openpgp.operator.jcajce.JcePublicKeyKeyEncryptionMethodGenerator;

import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.security.NoSuchProviderException;
import java.security.SecureRandom;
import java.security.Security;
import java.util.Iterator;


/**
 * Taken from org.bouncycastle.openpgp.examples
 *
 * @author seamans
 * @author jdamico <damico@dcon.com.br>
 */
public class PgpHelper {

    private static PgpHelper INSTANCE = null;

    public static PgpHelper getInstance() {

        if (INSTANCE == null) INSTANCE = new PgpHelper();
        return INSTANCE;
    }

    static {
        Security.insertProviderAt(new org.spongycastle.jce.provider.BouncyCastleProvider(), 1);
        Security.addProvider(new org.spongycastle.jce.provider.BouncyCastleProvider());
    }

    private PgpHelper() {
    }


    public PGPPublicKey readPublicKey(InputStream in) throws IOException, PGPException {

        in = org.spongycastle.openpgp.PGPUtil.getDecoderStream(in);

        PGPPublicKeyRingCollection pgpPub = new PGPPublicKeyRingCollection(in);

        //
        // we just loop through the collection till we find a key suitable for encryption, in the real
        // world you would probably want to be a bit smarter about this.
        //
        PGPPublicKey key = null;

        //
        // iterate through the key rings.
        //
        Iterator<PGPPublicKeyRing> rIt = pgpPub.getKeyRings();

        while (key == null && rIt.hasNext()) {
            PGPPublicKeyRing kRing = rIt.next();
            Iterator<PGPPublicKey> kIt = kRing.getPublicKeys();
            while (key == null && kIt.hasNext()) {
                PGPPublicKey k = kIt.next();

                if (k.isEncryptionKey()) {
                    key = k;
                }
            }
        }

        if (key == null) {
            throw new IllegalArgumentException("Can't find encryption key in key ring.");
        }

        return key;
    }

    /**
     * Load a secret key ring collection from keyIn and find the secret key corresponding to
     * keyID if it exists.
     *
     * @param keyIn input stream representing a key ring collection.
     * @param keyID keyID we want.
     * @param pass  passphrase to decrypt secret key with.
     * @return
     * @throws IOException
     * @throws PGPException
     * @throws NoSuchProviderException
     */
    public PGPPrivateKey findSecretKey(InputStream keyIn, long keyID, char[] pass)
            throws IOException, PGPException, NoSuchProviderException {
        PGPSecretKeyRingCollection pgpSec = new PGPSecretKeyRingCollection(
                PGPUtil.getDecoderStream(keyIn));

        PGPSecretKey pgpSecKey = pgpSec.getSecretKey(keyID);

        if (pgpSecKey == null) {
            return null;
        }

        PBESecretKeyDecryptor a = new JcePBESecretKeyDecryptorBuilder(new JcaPGPDigestCalculatorProviderBuilder().setProvider("BC").build()).setProvider("BC").build(pass);

        return pgpSecKey.extractPrivateKey(a);
    }


    /**
     * decrypt the passed in message stream
     */
    @SuppressWarnings("unchecked")
    public void decryptFile(InputStream in, OutputStream out, InputStream keyIn, char[] passwd)
            throws Exception {
        //Security.addProvider(new SpongyCastleProvider());

        in = 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();
        }

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

        while (sKey == null && it.hasNext()) {
            pbe = it.next();
            sKey = findSecretKey(keyIn, pbe.getKeyID(), passwd);
        }

        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);

        Object message = plainFact.nextObject();

        if (message instanceof PGPCompressedData) {
            PGPCompressedData cData = (PGPCompressedData) message;
            PGPObjectFactory pgpFact = new PGPObjectFactory(cData.getDataStream());

            message = pgpFact.nextObject();
        }

        if (message instanceof PGPLiteralData) {
            PGPLiteralData ld = (PGPLiteralData) message;
            InputStream unc = ld.getInputStream();
            int ch;
            while ((ch = unc.read()) >= 0) {
                out.write(ch);
            }
        } 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");
            }
        }
    }

    public void encryptStream(OutputStream out, InputStream in,String fileName, long fileLength, java.util.Date fileMod,
                            PGPPublicKey encKey, boolean armor, boolean withIntegrityCheck)
            throws IOException, NoSuchProviderException, PGPException {

        if (armor) {
            out = new ArmoredOutputStream(out);
        }

        ByteArrayOutputStream bOut = new ByteArrayOutputStream();

        PGPCompressedDataGenerator comData = new PGPCompressedDataGenerator(
                PGPCompressedData.ZIP);

        PGPLiteralDataGenerator lData = new PGPLiteralDataGenerator();
        OutputStream pOut = lData.open(out, PGPLiteralData.BINARY, fileName, fileLength, fileMod);

        IOUtils.copy(in, pOut);

        pOut.close();
        in.close();

        comData.close();

        BcPGPDataEncryptorBuilder c = new BcPGPDataEncryptorBuilder(PGPEncryptedData.AES_256).setWithIntegrityPacket(withIntegrityCheck).setSecureRandom(new SecureRandom());//.setProvider("BC");

        PGPEncryptedDataGenerator cPk = new PGPEncryptedDataGenerator(c);

        JcePublicKeyKeyEncryptionMethodGenerator d = new JcePublicKeyKeyEncryptionMethodGenerator(encKey).setProvider(new org.spongycastle.jce.provider.BouncyCastleProvider()).setSecureRandom(new SecureRandom());

        cPk.addMethod(d);

        byte[] bytes = bOut.toByteArray();

        OutputStream cOut = cPk.open(out, bytes.length);

        cOut.write(bytes);

        cOut.close();

        out.close();
    }

    public void encryptFile(OutputStream out, String fileName,
                            PGPPublicKey encKey, boolean armor, boolean withIntegrityCheck)
            throws IOException, NoSuchProviderException, PGPException {

        if (armor) {
            out = new ArmoredOutputStream(out);
        }

        ByteArrayOutputStream bOut = new ByteArrayOutputStream();

        PGPCompressedDataGenerator comData = new PGPCompressedDataGenerator(
                PGPCompressedData.ZIP);

        PGPUtil.writeFileToLiteralData(comData.open(bOut),
                PGPLiteralData.BINARY, new File(fileName));

        comData.close();

        JcePGPDataEncryptorBuilder c = new JcePGPDataEncryptorBuilder(PGPEncryptedData.CAST5).setWithIntegrityPacket(withIntegrityCheck).setSecureRandom(new SecureRandom()).setProvider("BC");

        PGPEncryptedDataGenerator cPk = new PGPEncryptedDataGenerator(c);

        JcePublicKeyKeyEncryptionMethodGenerator d = new JcePublicKeyKeyEncryptionMethodGenerator(encKey).setProvider(new org.spongycastle.jce.provider.BouncyCastleProvider()).setSecureRandom(new SecureRandom());

        cPk.addMethod(d);

        byte[] bytes = bOut.toByteArray();

        OutputStream cOut = cPk.open(out, bytes.length);

        cOut.write(bytes);

        cOut.close();

        out.close();
    }

}