/*
* Copyright 2010, 2011 sshj contributors
*
* Licensed 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.
*
* This file may incorporate work covered by the following copyright and
* permission notice:
*
* 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 net.schmizz.sshj.transport.cipher;
import net.schmizz.sshj.common.SSHRuntimeException;
import net.schmizz.sshj.common.SecurityUtils;
import javax.crypto.ShortBufferException;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;
import java.security.GeneralSecurityException;
/** Base class for all Cipher implementations delegating to the JCE provider. */
public class BaseCipher
implements Cipher {
private static byte[] resize(byte[] data, int size) {
if (data.length > size) {
final byte[] tmp = new byte[size];
System.arraycopy(data, 0, tmp, 0, size);
data = tmp;
}
return data;
}
private final int ivsize;
private final int bsize;
private final String algorithm;
private final String transformation;
private javax.crypto.Cipher cipher;
public BaseCipher(int ivsize, int bsize, String algorithm, String transformation) {
this.ivsize = ivsize;
this.bsize = bsize;
this.algorithm = algorithm;
this.transformation = transformation;
}
@Override
public int getBlockSize() {
return bsize;
}
@Override
public int getIVSize() {
return ivsize;
}
@Override
public void init(Mode mode, byte[] key, byte[] iv) {
key = BaseCipher.resize(key, bsize);
iv = BaseCipher.resize(iv, ivsize);
try {
cipher = SecurityUtils.getCipher(transformation);
cipher.init((mode == Mode.Encrypt ? javax.crypto.Cipher.ENCRYPT_MODE : javax.crypto.Cipher.DECRYPT_MODE),
new SecretKeySpec(key, algorithm), new IvParameterSpec(iv));
} catch (GeneralSecurityException e) {
cipher = null;
throw new SSHRuntimeException(e);
}
}
@Override
public void update(byte[] input, int inputOffset, int inputLen) {
try {
cipher.update(input, inputOffset, inputLen, input, inputOffset);
} catch (ShortBufferException e) {
throw new SSHRuntimeException(e);
}
}
}