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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

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 */

package com.sun.crypto.provider;

import java.security.InvalidKeyException;

/**

 * This abstract class represents the core of all block ciphers. It allows to

 * intialize the cipher and encrypt/decrypt single blocks. Larger quantities

 * are handled by modes, which are subclasses of FeedbackCipher.

 *

 * @author Gigi Ankeny

 * @author Jan Luehe

 *

 *

 * @see AESCrypt

 * @see DESCrypt

 * @see DESedeCrypt

 * @see BlowfishCrypt

 * @see FeedbackCipher

 */

abstract class SymmetricCipher {

    SymmetricCipher() {

        // empty

    }

    /**

     * Retrieves this cipher's block size.

     *

     * @return the block size of this cipher

     */

    abstract int getBlockSize();

    /**

     * Initializes the cipher in the specified mode with the given key.

     *

     * @param decrypting flag indicating encryption or decryption

     * @param algorithm the algorithm name

     * @param key the key

     *

     * @exception InvalidKeyException if the given key is inappropriate for

     * initializing this cipher

     */

    abstract void init(boolean decrypting, String algorithm, byte[] key)

        throws InvalidKeyException;

    /**

     * Encrypt one cipher block.

     *

     * <p>The input <code>plain</code>, starting at <code>plainOffset</code>

     * and ending at <code>(plainOffset+blockSize-1)</code>, is encrypted.

     * The result is stored in <code>cipher</code>, starting at

     * <code>cipherOffset</code>.

     *

     * @param plain the input buffer with the data to be encrypted

     * @param plainOffset the offset in <code>plain</code>

     * @param cipher the buffer for the encryption result

     * @param cipherOffset the offset in <code>cipher</code>

     */

    abstract void encryptBlock(byte[] plain, int plainOffset,

                          byte[] cipher, int cipherOffset);

    /**

     * Decrypt one cipher block.

     *

     * <p>The input <code>cipher</code>, starting at <code>cipherOffset</code>

     * and ending at <code>(cipherOffset+blockSize-1)</code>, is decrypted.

     * The result is stored in <code>plain</code>, starting at

     * <code>plainOffset</code>.

     *

     * @param cipher the input buffer with the data to be decrypted

     * @param cipherOffset the offset in <code>cipher</code>

     * @param plain the buffer for the decryption result

     * @param plainOffset the offset in <code>plain</code>

     */

    abstract void decryptBlock(byte[] cipher, int cipherOffset,

                          byte[] plain, int plainOffset);

}