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HBCI4j - Home Banking Computer Interface for Java - Clone from https://github.com/hbci4j/hbci4java
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/*  $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 javax.crypto.*;
import javax.crypto.spec.DESKeySpec;
import javax.crypto.spec.DESedeKeySpec;
import javax.crypto.spec.IvParameterSpec;
import java.security.InvalidKeyException;
import java.security.Key;
import java.security.NoSuchAlgorithmException;
import java.security.spec.InvalidKeySpecException;
import java.util.Arrays;

// 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;
    }
}