| /** |
| * 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 { |
| } |
| } |