gobblin.crypto.GPGFileDecryptor.java Source code

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Here is the source code for gobblin.crypto.GPGFileDecryptor.java

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/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package gobblin.crypto;

import java.io.IOException;
import java.io.InputStream;
import java.security.Security;

import org.bouncycastle.jce.provider.BouncyCastleProvider;
import org.bouncycastle.openpgp.PGPCompressedData;
import org.bouncycastle.openpgp.PGPEncryptedDataList;
import org.bouncycastle.openpgp.PGPException;
import org.bouncycastle.openpgp.PGPLiteralData;
import org.bouncycastle.openpgp.PGPPBEEncryptedData;
import org.bouncycastle.openpgp.PGPUtil;
import org.bouncycastle.openpgp.jcajce.JcaPGPObjectFactory;
import org.bouncycastle.openpgp.operator.jcajce.JcaPGPDigestCalculatorProviderBuilder;
import org.bouncycastle.openpgp.operator.jcajce.JcePBEDataDecryptorFactoryBuilder;

/**
 * A utility class that decrypts password based encryption files.
 *
 * Code reference - org.bouncycastle.openpgp.examples.PBEFileProcessor
 */
public class GPGFileDecryptor {

    public static InputStream decryptFile(InputStream inputStream, String passPhrase) throws IOException {

        if (Security.getProvider(BouncyCastleProvider.PROVIDER_NAME) == null) {
            Security.addProvider(new BouncyCastleProvider());
        }
        inputStream = PGPUtil.getDecoderStream(inputStream);

        JcaPGPObjectFactory pgpF = new JcaPGPObjectFactory(inputStream);
        PGPEncryptedDataList enc;
        Object pgpfObject = pgpF.nextObject();

        if (pgpfObject instanceof PGPEncryptedDataList) {
            enc = (PGPEncryptedDataList) pgpfObject;
        } else {
            enc = (PGPEncryptedDataList) pgpF.nextObject();
        }

        PGPPBEEncryptedData pbe = (PGPPBEEncryptedData) enc.get(0);

        InputStream clear;
        try {
            clear = pbe
                    .getDataStream(new JcePBEDataDecryptorFactoryBuilder(new JcaPGPDigestCalculatorProviderBuilder()
                            .setProvider(BouncyCastleProvider.PROVIDER_NAME).build())
                                    .setProvider(BouncyCastleProvider.PROVIDER_NAME)
                                    .build(passPhrase.toCharArray()));

            JcaPGPObjectFactory pgpFact = new JcaPGPObjectFactory(clear);
            pgpfObject = pgpFact.nextObject();
            if (pgpfObject instanceof PGPCompressedData) {
                PGPCompressedData cData = (PGPCompressedData) pgpfObject;
                pgpFact = new JcaPGPObjectFactory(cData.getDataStream());
                pgpfObject = pgpFact.nextObject();
            }

            PGPLiteralData ld = (PGPLiteralData) pgpfObject;
            return ld.getInputStream();
        } catch (PGPException e) {
            throw new IOException(e);
        }
    }
}