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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 org.apache.sshd.common.cipher;

import org.apache.sshd.common.util.SecurityUtils;

import javax.crypto.spec.SecretKeySpec;

/**
 * @author <a href="mailto:dev@mina.apache.org">Apache MINA SSHD Project</a>
 */

public class BaseRC4Cipher extends BaseCipher {

    public static final int     SKIP_SIZE = 1536;

    public BaseRC4Cipher(int ivsize, int bsize) {
        super(ivsize, bsize, "ARCFOUR", "RC4");
    }

    @Override
    public void init(Mode mode, byte[] key, byte[] iv) throws Exception {
        key = resize(key, bsize);
        try {
            cipher = SecurityUtils.getCipher(transformation);
            cipher.init((mode == Mode.Encrypt ? javax.crypto.Cipher.ENCRYPT_MODE : javax.crypto.Cipher.DECRYPT_MODE),
                    new SecretKeySpec(key, algorithm));

            byte[] foo = new byte[1];
            for (int i = 0; i < SKIP_SIZE; i++) {
                cipher.update(foo, 0, 1, foo, 0);
            }
        } catch (Exception e) {
            cipher = null;
            throw e;
        }
    }

}