de.mibos.commons.crypt.CryptOutputStream Maven / Gradle / Ivy

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/*
 * Copyright 2014 Michael Bock
 *
 * 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 de.mibos.commons.crypt;

import javax.annotation.Nonnull;
import javax.crypto.Cipher;
import javax.crypto.CipherOutputStream;
import java.io.FilterOutputStream;
import java.io.IOException;
import java.io.OutputStream;

/**
 * An output stream for the specified {@link de.mibos.commons.crypt.Crypt}.
 * This is simply an extension to the standard {@link javax.crypto.CipherOutputStream}, which
 * writes the initialization vector in the constructor. So both constructors may throw an {@link java.io.IOException}, if failing
 * to write the initialization vector.
 * Please ensure that close is always called explicitly for this stream object. Failing to do so will result in
 * missing cipher text bytes.
 *
 * @author Michael Bock
 * @version 1.5
 * @since 1.3
 * Id: CryptOutputStream.java 45 2014-09-20 19:04:30Z michaels-apps $
 */
public class CryptOutputStream extends FilterOutputStream {

    /**
     * An output stream for the specified {@link de.mibos.commons.crypt.Crypt}.
     * This is simply an extension to the standard {@link javax.crypto.CipherOutputStream}, which
     * writes the initialization vector in the constructor. So this constructor may throw an {@link java.io.IOException}, if failing
     * to write the initialization vector.

     * 
     * In contrast to the {@link javax.crypto.CipherOutputStream} it only supports encrypting a plain text, not decrypting a cipher text.

     * 
     * Please ensure that close is always called explicitly for this stream object. Failing to do so will result in
     * missing cipher text bytes.
     *
     * @param crypt    the used {@link de.mibos.commons.crypt.Crypt} object
     * @param output   the cipher output stream
     * @param password the password
     * @throws IOException                 {@link java.io.IOException} if failing to write the initialization vector
     * @throws CryptoInitializationProblem in case of a {@link de.mibos.commons.crypt.CryptoInitializationProblem} problem
     */
    public CryptOutputStream(@Nonnull final Crypt crypt, @Nonnull final OutputStream output, @Nonnull final CharSequence password) throws IOException {
        //noinspection ConstantConditions
        super(null);
        final byte[] passwordBytes = crypt.getHashedEncryptionKey(password);
        initCipher(crypt, output, passwordBytes);
        crypt.resetPasswordBytes(passwordBytes);
    }

    /**
     * An output stream for the specified {@link de.mibos.commons.crypt.Crypt}.
     * This is simply an extension to the standard {@link javax.crypto.CipherOutputStream}, which
     * writes the initialization vector in the constructor. So this constructor may throw an {@link java.io.IOException}, if failing
     * to write the initialization vector.
     * Please ensure that close is always called explicitly for this stream object. Failing to do so will result in
     * missing cipher text bytes.
     *
     * @param crypt         the used {@link de.mibos.commons.crypt.Crypt} object
     * @param output        the cipher output stream
     * @param passwordBytes the password bytes
     * @throws IOException                 {@link java.io.IOException} if failing to write the initialization vector
     * @throws CryptoInitializationProblem in case of a {@link de.mibos.commons.crypt.CryptoInitializationProblem} problem
     */
    public CryptOutputStream(@Nonnull final Crypt crypt, @Nonnull final OutputStream output, @Nonnull final byte[] passwordBytes) throws IOException {
        //noinspection ConstantConditions
        super(null);
        initCipher(crypt, output, passwordBytes);
    }

    /**
     * Initializes the underlying {@link javax.crypto.CipherOutputStream}
     *
     * @param crypt         the used {@link de.mibos.commons.crypt.Crypt} object
     * @param output        the cipher output stream
     * @param passwordBytes the password bytes
     * @throws IOException                 {@link java.io.IOException} if failing to write the initialization vector
     * @throws CryptoInitializationProblem in case of a {@link de.mibos.commons.crypt.CryptoInitializationProblem} problem
     */
    private void initCipher(@Nonnull Crypt crypt, @Nonnull OutputStream output, @Nonnull byte[] passwordBytes) throws IOException {
        final Cipher cipher = crypt.getEncryptionCipher(passwordBytes);
        final byte[] iv = cipher.getIV();
        output.write(iv);
        this.out = new CipherOutputStream(output, cipher);
    }
}