org.apache.hadoop.crypto.AesCtrCryptoCodec Maven / Gradle / Ivy
/**
* 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.hadoop.crypto;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;
import org.apache.hadoop.thirdparty.com.google.common.base.Preconditions;
import java.io.IOException;
@InterfaceAudience.Private
@InterfaceStability.Evolving
public abstract class AesCtrCryptoCodec extends CryptoCodec {
protected static final CipherSuite SUITE = CipherSuite.AES_CTR_NOPADDING;
/**
* For AES, the algorithm block is fixed size of 128 bits.
* @see http://en.wikipedia.org/wiki/Advanced_Encryption_Standard
*/
private static final int AES_BLOCK_SIZE = SUITE.getAlgorithmBlockSize();
@Override
public CipherSuite getCipherSuite() {
return SUITE;
}
/**
* The IV is produced by adding the initial IV to the counter. IV length
* should be the same as {@link #AES_BLOCK_SIZE}
*/
@Override
public void calculateIV(byte[] initIV, long counter, byte[] IV) {
Preconditions.checkArgument(initIV.length == AES_BLOCK_SIZE);
Preconditions.checkArgument(IV.length == AES_BLOCK_SIZE);
int i = IV.length; // IV length
int j = 0; // counter bytes index
int sum = 0;
while (i-- > 0) {
// (sum >>> Byte.SIZE) is the carry for addition
sum = (initIV[i] & 0xff) + (sum >>> Byte.SIZE);
if (j++ < 8) { // Big-endian, and long is 8 bytes length
sum += (byte) counter & 0xff;
counter >>>= 8;
}
IV[i] = (byte) sum;
}
}
@Override
public void close() throws IOException {
}
}