/*
* 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 javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;
import org.apache.sshd.common.SshException;
import org.apache.sshd.common.util.ValidateUtils;
import org.apache.sshd.common.util.security.SecurityUtils;
/**
* Base class for all Cipher implementations delegating to the JCE provider.
*
* @author <a href="mailto:dev@mina.apache.org">Apache MINA SSHD Project</a>
*/
public class BaseCipher implements Cipher {
protected javax.crypto.Cipher cipher;
private final int ivsize;
private final int bsize;
private final String algorithm;
private final String transformation;
private String s;
public BaseCipher(int ivsize, int bsize, String algorithm, String transformation) {
this.ivsize = ivsize;
this.bsize = bsize;
this.algorithm = ValidateUtils.checkNotNullAndNotEmpty(algorithm, "No algorithm");
this.transformation = ValidateUtils.checkNotNullAndNotEmpty(transformation, "No transformation");
}
@Override
public String getAlgorithm() {
return algorithm;
}
@Override
public String getTransformation() {
return transformation;
}
@Override
public int getIVSize() {
return ivsize;
}
@Override
public int getBlockSize() {
return bsize;
}
@Override
public void init(Mode mode, byte[] key, byte[] iv) throws Exception {
key = resize(key, getBlockSize());
iv = resize(iv, getIVSize());
try {
cipher = SecurityUtils.getCipher(getTransformation());
cipher.init(Mode.Encrypt.equals(mode) ? javax.crypto.Cipher.ENCRYPT_MODE : javax.crypto.Cipher.DECRYPT_MODE,
new SecretKeySpec(key, getAlgorithm()),
new IvParameterSpec(iv));
} catch (Exception e) {
cipher = null;
throw new SshException("Unable to initialize cipher " + this, e);
}
}
@Override
public void update(byte[] input, int inputOffset, int inputLen) throws Exception {
cipher.update(input, inputOffset, inputLen, input, inputOffset);
}
protected static byte[] resize(byte[] data, int size) {
if (data.length > size) {
byte[] tmp = new byte[size];
System.arraycopy(data, 0, tmp, 0, size);
data = tmp;
}
return data;
}
@Override
public String toString() {
synchronized (this) {
if (s == null) {
s = getClass().getSimpleName()
+ "[" + getAlgorithm()
+ "," + getIVSize()
+ "," + getBlockSize()
+ "," + getTransformation()
+ "]";
}
}
return s;
}
}