/* $Id: RetailMAC.java,v 1.1 2011/05/04 22:37:58 willuhn Exp $
This file is part of CryptAlgs4Java
Copyright (C) 2001-2010 Stefan Palme
CryptAlgs4Java is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
CryptAlgs4Java 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 for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
package org.kapott.cryptalgs;
import java.security.InvalidKeyException;
import java.security.Key;
import java.security.NoSuchAlgorithmException;
import java.security.spec.InvalidKeySpecException;
import java.util.Arrays;
import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESKeySpec;
import javax.crypto.spec.DESedeKeySpec;
import javax.crypto.spec.IvParameterSpec;
// TODO: implement some SPI interface?
public class RetailMAC
{
private SecretKey deskey;
private SecretKey desedekey;
private IvParameterSpec ivspec;
private byte[] buffer=new byte[16];
private int offset;
private byte[] c=new byte[8];
private Cipher cipher;
public RetailMAC(Key key,IvParameterSpec iv)
{
try {
SecretKeyFactory fac=SecretKeyFactory.getInstance("DESede");
DESedeKeySpec spec=(DESedeKeySpec)fac.getKeySpec((SecretKey)key,
DESedeKeySpec.class);
byte[] desedekeydata=spec.getKey();
DESKeySpec spec2=new DESKeySpec(desedekeydata);
fac=SecretKeyFactory.getInstance("DES");
this.deskey=fac.generateSecret(spec2);
this.desedekey=(SecretKey)key;
this.ivspec=iv;
this.cipher=Cipher.getInstance("DES");
reset();
} catch (InvalidKeyException e) {
throw new RuntimeException(e);
} catch (NoSuchAlgorithmException e) {
throw new RuntimeException(e);
} catch (InvalidKeySpecException e) {
throw new RuntimeException(e);
} catch (NoSuchPaddingException e) {
throw new RuntimeException(e);
}
}
public byte[] doFinal(byte[] data)
{
update(data,0,data.length);
return doFinal();
}
public byte[] doFinal()
{
for (int i=0;i<8;i++) {
this.buffer[i]^=this.c[i];
}
try {
Cipher cipher2=Cipher.getInstance("DESede");
cipher2.init(Cipher.ENCRYPT_MODE, this.desedekey);
this.c=cipher2.doFinal(this.buffer, 0, 8);
} catch (InvalidKeyException e) {
throw new RuntimeException(e);
} catch (NoSuchAlgorithmException e) {
throw new RuntimeException(e);
} catch (NoSuchPaddingException e) {
throw new RuntimeException(e);
} catch (IllegalBlockSizeException e) {
throw new RuntimeException(e);
} catch (BadPaddingException e) {
throw new RuntimeException(e);
}
byte[] ret=new byte[8];
System.arraycopy(this.c, 0, ret, 0, 8);
reset();
return ret;
}
public void update(byte data)
{
this.buffer[this.offset++]=data;
if (this.offset>8) {
hashIt();
}
}
public void reset()
{
Arrays.fill(this.buffer,(byte)0);
System.arraycopy(this.ivspec.getIV(), 0, this.c, 0, 8);
this.offset=0;
}
public int getMacLength()
{
return 8;
}
public void update(byte[] ibuffer,int offset1,int len)
{
for (int i=0;i<len;i++)
update(ibuffer[offset1+i]);
}
private void hashIt()
{
for (int i=0;i<8;i++) {
this.buffer[i]^=this.c[i];
}
try {
this.cipher.init(Cipher.ENCRYPT_MODE, this.deskey);
this.c=this.cipher.doFinal(this.buffer, 0, 8);
} catch (InvalidKeyException e) {
throw new RuntimeException(e);
} catch (IllegalBlockSizeException e) {
throw new RuntimeException(e);
} catch (BadPaddingException e) {
throw new RuntimeException(e);
}
System.arraycopy(this.buffer,8, this.buffer,0, 8);
Arrays.fill(this.buffer, 8, 16, (byte)0);
this.offset-=8;
}
}