| /* |
| * 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 javax.crypto.spec; |
| |
| import java.security.InvalidKeyException; |
| import java.security.spec.KeySpec; |
| |
| /** |
| * The key specification for a triple-DES (DES-EDE) key. |
| */ |
| public class DESedeKeySpec implements KeySpec { |
| |
| /** |
| * The length of a DES-EDE key in bytes. |
| */ |
| public static final int DES_EDE_KEY_LEN = 24; |
| |
| private final byte[] key; |
| |
| /** |
| * Creates a new <code>DESedeKeySpec</code> instance from the first 24 ( |
| * {@link #DES_EDE_KEY_LEN}) bytes of the specified key data. |
| * |
| * @param key |
| * the key data. |
| * @throws InvalidKeyException |
| * if the length of the key data is less than 24. |
| * @throws NullPointerException |
| * if the key data is null. |
| */ |
| public DESedeKeySpec(byte[] key) throws InvalidKeyException { |
| if (key == null) { |
| throw new NullPointerException(); |
| } |
| if (key.length < DES_EDE_KEY_LEN) { |
| throw new InvalidKeyException(); |
| } |
| this.key = new byte[DES_EDE_KEY_LEN]; |
| System.arraycopy(key, 0, this.key, 0, DES_EDE_KEY_LEN); |
| } |
| |
| /** |
| * Creates a new <code>DESedeKeySpec</code> instance from the first 24 ( |
| * {@link #DES_EDE_KEY_LEN} ) bytes of the specified key data starting at |
| * <code>offset</code>. |
| * |
| * @param key |
| * the key data |
| * @param offset |
| * the offset to start at. |
| * @throws InvalidKeyException |
| * if the length of the key data starting at offset is less than |
| * 24. |
| * @throws NullPointerException |
| * if the key data is null. |
| */ |
| public DESedeKeySpec(byte[] key, int offset) throws InvalidKeyException { |
| if (key == null) { |
| throw new NullPointerException(); |
| } |
| if (key.length - offset < DES_EDE_KEY_LEN) { |
| throw new InvalidKeyException(); |
| } |
| this.key = new byte[DES_EDE_KEY_LEN]; |
| System.arraycopy(key, offset, this.key, 0, DES_EDE_KEY_LEN); |
| } |
| |
| /** |
| * Returns a copy of the key. |
| * |
| * @return a copy of the key. |
| */ |
| public byte[] getKey() { |
| byte[] result = new byte [DES_EDE_KEY_LEN]; |
| System.arraycopy(this.key, 0, result, 0, DES_EDE_KEY_LEN); |
| return result; |
| } |
| |
| /** |
| * Returns whether the specified key data starting at <code>offset</code> is |
| * <i>parity-adjusted</i>. |
| * |
| * @param key |
| * the key data. |
| * @param offset |
| * the offset to start checking at. |
| * @return {@code true} if the specified key data is parity-adjusted, |
| * {@code false} otherwise. |
| * @throws InvalidKeyException |
| * if the length of the key data starting at offset is less than |
| * 24. |
| */ |
| public static boolean isParityAdjusted(byte[] key, int offset) throws InvalidKeyException { |
| if (key.length - offset < DES_EDE_KEY_LEN) { |
| throw new InvalidKeyException(); |
| } |
| for (int i=offset; i<DES_EDE_KEY_LEN+offset; i++) { |
| int b = key[i]; |
| if ((((b & 1) + ((b & 2) >> 1) + ((b & 4) >> 2) |
| + ((b & 8) >> 3) + ((b & 16) >> 4) + ((b & 32) >> 5) |
| + ((b & 64) >> 6)) & 1) == ((b & 128) >> 7)) { |
| return false; |
| } |
| } |
| return true; |
| } |
| } |