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/*
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
/*
* (C) Copyright IBM Corp. 1999 All Rights Reserved.
* Copyright 1997 The Open Group Research Institute. All rights reserved.
*/
package sun.security.krb5.internal.crypto;
import sun.security.krb5.Checksum;
import sun.security.krb5.KrbCryptoException;
import sun.security.krb5.internal.*;
import javax.crypto.spec.DESKeySpec;
import java.security.InvalidKeyException;
public class DesMacKCksumType extends CksumType {
public DesMacKCksumType() {
}
public int confounderSize() {
return 0;
}
public int cksumType() {
return Checksum.CKSUMTYPE_DES_MAC_K;
}
public boolean isKeyed() {
return true;
}
public int cksumSize() {
return 16;
}
public int keyType() {
return Krb5.KEYTYPE_DES;
}
public int keySize() {
return 8;
}
/**
* Calculates keyed checksum.
* @param data the data used to generate the checksum.
* @param size length of the data.
* @param key the key used to encrypt the checksum.
* @return keyed checksum.
*
* @modified by Yanni Zhang, 12/08/99.
*/
public byte[] calculateChecksum(byte[] data, int size, byte[] key,
int usage) throws KrbCryptoException {
//check for weak keys
try {
if (DESKeySpec.isWeak(key, 0)) {
key[7] = (byte)(key[7] ^ 0xF0);
}
} catch (InvalidKeyException ex) {
// swallow, since it should never happen
}
byte[] ivec = new byte[key.length];
System.arraycopy(key, 0, ivec, 0, key.length);
byte[] cksum = Des.des_cksum(ivec, data, key);
return cksum;
}
public boolean verifyChecksum(byte[] data, int size,
byte[] key, byte[] checksum, int usage) throws KrbCryptoException {
byte[] new_cksum = calculateChecksum(data, data.length, key, usage);
return isChecksumEqual(checksum, new_cksum);
}
}
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