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*
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* published by the Free Software Foundation. Oracle designates this
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*
* This code is distributed in the hope that it will be useful, but WITHOUT
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* 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,
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/*
* (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.Confounder;
import sun.security.krb5.KrbCryptoException;
import sun.security.krb5.internal.*;
import javax.crypto.spec.DESKeySpec;
import java.security.InvalidKeyException;
public class DesMacCksumType extends CksumType {
public DesMacCksumType() {
}
public int confounderSize() {
return 8;
}
public int cksumType() {
return Checksum.CKSUMTYPE_DES_MAC;
}
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.
Params: - data – the data used to generate the checksum.
- size – length of the data.
- key – the key used to encrypt the checksum.
Returns: keyed checksum. @modified by Yanni Zhang, 12/08/99.
/**
* 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 {
byte[] new_data = new byte[size + confounderSize()];
byte[] conf = Confounder.bytes(confounderSize());
System.arraycopy(conf, 0, new_data, 0, confounderSize());
System.arraycopy(data, 0, new_data, confounderSize(), size);
//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[] residue_ivec = new byte[key.length];
byte[] residue = Des.des_cksum(residue_ivec, new_data, key);
byte[] cksum = new byte[cksumSize()];
System.arraycopy(conf, 0, cksum, 0, confounderSize());
System.arraycopy(residue, 0, cksum, confounderSize(),
cksumSize() - confounderSize());
byte[] new_key = new byte[keySize()];
System.arraycopy(key, 0, new_key, 0, key.length);
for (int i = 0; i < new_key.length; i++)
new_key[i] = (byte)(new_key[i] ^ 0xf0);
//check for weak keys
try {
if (DESKeySpec.isWeak(new_key, 0)) {
new_key[7] = (byte)(new_key[7] ^ 0xF0);
}
} catch (InvalidKeyException ex) {
// swallow, since it should never happen
}
byte[] ivec = new byte[new_key.length];
//des-cbc encrypt
byte[] enc_cksum = new byte[cksum.length];
Des.cbc_encrypt(cksum, enc_cksum, new_key, ivec, true);
return enc_cksum;
}
Verifies keyed checksum.
Params: - data – the data.
- size – the length of data.
- key – the key used to encrypt the checksum.
- checksum – the checksum.
Returns: true if verification is successful. @modified by Yanni Zhang, 12/08/99.
/**
* Verifies keyed checksum.
* @param data the data.
* @param size the length of data.
* @param key the key used to encrypt the checksum.
* @param checksum the checksum.
* @return true if verification is successful.
*
* @modified by Yanni Zhang, 12/08/99.
*/
public boolean verifyChecksum(byte[] data, int size,
byte[] key, byte[] checksum, int usage) throws KrbCryptoException {
byte[] cksum = decryptKeyedChecksum(checksum, key);
byte[] new_data = new byte[size + confounderSize()];
System.arraycopy(cksum, 0, new_data, 0, confounderSize());
System.arraycopy(data, 0, new_data, confounderSize(), size);
//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];
byte[] new_cksum = Des.des_cksum(ivec, new_data, key);
byte[] orig_cksum = new byte[cksumSize() - confounderSize()];
System.arraycopy(cksum, confounderSize(), orig_cksum, 0,
cksumSize() - confounderSize());
return isChecksumEqual(orig_cksum, new_cksum);
}
Decrypts keyed checksum.
Params: - enc_cksum – the buffer for encrypted checksum.
- key – the key.
Returns: the checksum. @modified by Yanni Zhang, 12/08/99.
/**
* Decrypts keyed checksum.
* @param enc_cksum the buffer for encrypted checksum.
* @param key the key.
* @return the checksum.
*
* @modified by Yanni Zhang, 12/08/99.
*/
private byte[] decryptKeyedChecksum(byte[] enc_cksum, byte[] key) throws KrbCryptoException {
byte[] new_key = new byte[keySize()];
System.arraycopy(key, 0, new_key, 0, key.length);
for (int i = 0; i < new_key.length; i++)
new_key[i] = (byte)(new_key[i] ^ 0xf0);
//check for weak keys
try {
if (DESKeySpec.isWeak(new_key, 0)) {
new_key[7] = (byte)(new_key[7] ^ 0xF0);
}
} catch (InvalidKeyException ex) {
// swallow, since it should never happen
}
byte[] ivec = new byte[new_key.length];
byte[] cksum = new byte[enc_cksum.length];
Des.cbc_encrypt(enc_cksum, cksum, new_key, ivec, false);
return cksum;
}
}