182 lines
6.9 KiB
Java
182 lines
6.9 KiB
Java
/*
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* Copyright 2018 Paul Schaub.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package org.pgpainless.symmetric_encryption;
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import java.io.BufferedInputStream;
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import java.io.ByteArrayInputStream;
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import java.io.ByteArrayOutputStream;
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import java.io.IOException;
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import java.io.InputStream;
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import java.io.OutputStream;
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import java.security.SecureRandom;
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import java.util.Date;
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import org.bouncycastle.openpgp.PGPCompressedData;
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import org.bouncycastle.openpgp.PGPCompressedDataGenerator;
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import org.bouncycastle.openpgp.PGPEncryptedDataGenerator;
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import org.bouncycastle.openpgp.PGPEncryptedDataList;
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import org.bouncycastle.openpgp.PGPException;
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import org.bouncycastle.openpgp.PGPLiteralData;
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import org.bouncycastle.openpgp.PGPLiteralDataGenerator;
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import org.bouncycastle.openpgp.PGPPBEEncryptedData;
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import org.bouncycastle.openpgp.PGPUtil;
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import org.bouncycastle.openpgp.bc.BcPGPObjectFactory;
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import org.bouncycastle.openpgp.operator.bc.BcPBEDataDecryptorFactory;
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import org.bouncycastle.openpgp.operator.bc.BcPGPDigestCalculatorProvider;
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import org.bouncycastle.openpgp.operator.jcajce.JcePBEKeyEncryptionMethodGenerator;
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import org.bouncycastle.openpgp.operator.jcajce.JcePGPDataEncryptorBuilder;
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import org.bouncycastle.util.io.Streams;
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import org.pgpainless.algorithm.CompressionAlgorithm;
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import org.pgpainless.algorithm.SymmetricKeyAlgorithm;
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import org.pgpainless.util.Passphrase;
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/**
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* Stolen from <a href="https://github.com/bcgit/bc-java/blob/master/pg/src/main/java/org/bouncycastle/openpgp/examples/PBEFileProcessor.java">
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* Bouncycastle examples</a>.
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*/
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public class SymmetricEncryptorDecryptor {
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/**
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* Encrypt some {@code data} symmetrically using an {@code encryptionAlgorithm} and a given {@code password}.
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* The input data will be compressed using the given {@code compressionAlgorithm} and packed in a modification
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* detection package, which is then encrypted.
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*
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* @param data bytes that will be encrypted
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* @param password password that will be used to encrypt the data
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* @param encryptionAlgorithm symmetric algorithm that will be used to encrypt the data
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* @param compressionAlgorithm compression algorithm that will be used to compress the data
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* @return encrypted data
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* @throws IOException IO is dangerous
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* @throws PGPException OpenPGP is brittle
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*/
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public static byte[] symmetricallyEncrypt(byte[] data,
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Passphrase password,
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SymmetricKeyAlgorithm encryptionAlgorithm,
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CompressionAlgorithm compressionAlgorithm)
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throws IOException, PGPException {
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byte[] compressedData = compress(data, compressionAlgorithm.getAlgorithmId());
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ByteArrayOutputStream bOut = new ByteArrayOutputStream();
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PGPEncryptedDataGenerator encGen = new PGPEncryptedDataGenerator(
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new JcePGPDataEncryptorBuilder(encryptionAlgorithm.getAlgorithmId())
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.setWithIntegrityPacket(true)
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.setSecureRandom(new SecureRandom())
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.setProvider("BC"));
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encGen.addMethod(new JcePBEKeyEncryptionMethodGenerator(password.getChars()).setProvider("BC"));
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OutputStream encOut = encGen.open(bOut, compressedData.length);
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encOut.write(compressedData);
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encOut.close();
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return bOut.toByteArray();
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}
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/**
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* Decrypt and decompress some symmetrically encrypted data using a password.
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* Note, that decryption will fail if the given data is not integrity protected with a modification detection
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* package.
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*
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* @param data encrypted data
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* @param password password to decrypt the data
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* @return decrypted data
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* @throws IOException IO is dangerous
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* @throws PGPException OpenPGP is brittle
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*/
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public static byte[] symmetricallyDecrypt(byte[] data, Passphrase password) throws IOException, PGPException {
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InputStream in = new BufferedInputStream(new ByteArrayInputStream(data));
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in = PGPUtil.getDecoderStream(in);
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BcPGPObjectFactory pgpF = new BcPGPObjectFactory(in);
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PGPEncryptedDataList enc;
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Object o = pgpF.nextObject();
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if (o instanceof PGPEncryptedDataList) {
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enc = (PGPEncryptedDataList) o;
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} else {
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enc = (PGPEncryptedDataList) pgpF.nextObject();
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}
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PGPPBEEncryptedData pbe = (PGPPBEEncryptedData) enc.get(0);
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InputStream clear = pbe.getDataStream(new BcPBEDataDecryptorFactory(
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password.getChars(), new BcPGPDigestCalculatorProvider()));
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BcPGPObjectFactory pgpFact = new BcPGPObjectFactory(clear);
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o = pgpFact.nextObject();
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if (o instanceof PGPCompressedData) {
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PGPCompressedData cData = (PGPCompressedData) o;
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pgpFact = new BcPGPObjectFactory(cData.getDataStream());
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o = pgpFact.nextObject();
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}
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PGPLiteralData ld = (PGPLiteralData) o;
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InputStream unc = ld.getInputStream();
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ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
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Streams.pipeAll(unc, outputStream);
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outputStream.close();
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if (pbe.isIntegrityProtected()) {
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if (!pbe.verify()) {
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throw new PGPException("Integrity check failed.");
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}
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} else {
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throw new PGPException("Symmetrically encrypted data is not integrity protected.");
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}
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return outputStream.toByteArray();
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}
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/**
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* Wrap some data in an OpenPGP compressed data package.
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*
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* @param clearData uncompressed data
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* @param algorithm compression algorithm
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* @return compressed data
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* @throws IOException IO is dangerous
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*/
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private static byte[] compress(byte[] clearData, int algorithm) throws IOException {
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ByteArrayOutputStream bOut = new ByteArrayOutputStream();
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PGPCompressedDataGenerator comData = new PGPCompressedDataGenerator(algorithm);
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OutputStream cos = comData.open(bOut);
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PGPLiteralDataGenerator lData = new PGPLiteralDataGenerator();
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OutputStream pOut = lData.open(cos,
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PGPLiteralData.BINARY,
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PGPLiteralDataGenerator.CONSOLE,
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clearData.length,
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new Date()
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);
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pOut.write(clearData);
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pOut.close();
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comData.close();
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return bOut.toByteArray();
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}
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}
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