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DESedeEngine.javaAPI DocAndroid 1.5 API3543Wed May 06 22:41:06 BST 2009org.bouncycastle.crypto.engines

DESedeEngine

public class DESedeEngine extends DESEngine
a class that provides a basic DESede (or Triple DES) engine.

Fields Summary
protected static final int
BLOCK_SIZE
private int[]
workingKey1
private int[]
workingKey2
private int[]
workingKey3
private boolean
forEncryption
Constructors Summary
public DESedeEngine()
standard constructor.
Methods Summary
public java.lang.StringgetAlgorithmName()

        return "DESede";
public intgetBlockSize()

        return BLOCK_SIZE;
public voidinit(boolean encrypting, org.bouncycastle.crypto.CipherParameters params)
initialise a DESede cipher.

param
encrypting whether or not we are for encryption.
param
params the parameters required to set up the cipher.
exception
IllegalArgumentException if the params argument is inappropriate.

        if (!(params instanceof KeyParameter))
        {
            throw new IllegalArgumentException("invalid parameter passed to DESede init - " + params.getClass().getName());
        }

        byte[]      keyMaster = ((KeyParameter)params).getKey();
        byte[]      key1 = new byte[8], key2 = new byte[8], key3 = new byte[8];

        if (keyMaster.length > 24)
        {
            throw new IllegalArgumentException("key size greater than 24 bytes");
        }
        
        this.forEncryption = encrypting;

        if (keyMaster.length == 24)
        {
            System.arraycopy(keyMaster, 0, key1, 0, key1.length);
            System.arraycopy(keyMaster, 8, key2, 0, key2.length);
            System.arraycopy(keyMaster, 16, key3, 0, key3.length);

            workingKey1 = generateWorkingKey(encrypting, key1);
            workingKey2 = generateWorkingKey(!encrypting, key2);
            workingKey3 = generateWorkingKey(encrypting, key3);
        }
        else    // 16 byte key
        {
            System.arraycopy(keyMaster, 0, key1, 0, key1.length);
            System.arraycopy(keyMaster, 8, key2, 0, key2.length);

            workingKey1 = generateWorkingKey(encrypting, key1);
            workingKey2 = generateWorkingKey(!encrypting, key2);
            workingKey3 = workingKey1;
        }
public intprocessBlock(byte[] in, int inOff, byte[] out, int outOff)

        if (workingKey1 == null)
        {
            throw new IllegalStateException("DESede engine not initialised");
        }

        if ((inOff + BLOCK_SIZE) > in.length)
        {
            throw new DataLengthException("input buffer too short");
        }

        if ((outOff + BLOCK_SIZE) > out.length)
        {
            throw new DataLengthException("output buffer too short");
        }

        if (forEncryption)
        {
            desFunc(workingKey1, in, inOff, out, outOff);
            desFunc(workingKey2, out, outOff, out, outOff);
            desFunc(workingKey3, out, outOff, out, outOff);
        }
        else
        {
            desFunc(workingKey3, in, inOff, out, outOff);
            desFunc(workingKey2, out, outOff, out, outOff);
            desFunc(workingKey1, out, outOff, out, outOff);
        }

        return BLOCK_SIZE;
public voidreset()