package org.bouncycastle.crypto.engines;
import org.bouncycastle.crypto.BlockCipher;
import org.bouncycastle.crypto.CipherParameters;
import org.bouncycastle.crypto.DataLengthException;
import org.bouncycastle.crypto.OutputLengthException;
/**
* The no-op engine that just copies bytes through, irrespective of whether encrypting and decrypting.
* Provided for the sake of completeness.
*/
public class NullEngine implements BlockCipher
{
private boolean initialised;
protected static final int BLOCK_SIZE = 1;
/**
* Standard constructor.
*/
public NullEngine()
{
super();
}
/* (non-Javadoc)
* @see org.bouncycastle.crypto.BlockCipher#init(boolean, org.bouncycastle.crypto.CipherParameters)
*/
public void init(boolean forEncryption, CipherParameters params) throws IllegalArgumentException
{
// we don't mind any parameters that may come in
this.initialised = true;
}
/* (non-Javadoc)
* @see org.bouncycastle.crypto.BlockCipher#getAlgorithmName()
*/
public String getAlgorithmName()
{
return "Null";
}
/* (non-Javadoc)
* @see org.bouncycastle.crypto.BlockCipher#getBlockSize()
*/
public int getBlockSize()
{
return BLOCK_SIZE;
}
/* (non-Javadoc)
* @see org.bouncycastle.crypto.BlockCipher#processBlock(byte[], int, byte[], int)
*/
public int processBlock(byte[] in, int inOff, byte[] out, int outOff)
throws DataLengthException, IllegalStateException
{
if (!initialised)
{
throw new IllegalStateException("Null engine not initialised");
}
if ((inOff + BLOCK_SIZE) > in.length)
{
throw new DataLengthException("input buffer too short");
}
if ((outOff + BLOCK_SIZE) > out.length)
{
throw new OutputLengthException("output buffer too short");
}
for (int i = 0; i < BLOCK_SIZE; ++i)
{
out[outOff + i] = in[inOff + i];
}
return BLOCK_SIZE;
}
/* (non-Javadoc)
* @see org.bouncycastle.crypto.BlockCipher#reset()
*/
public void reset()
{
// nothing needs to be done
}
}