sicblockcipher.java

java 文件下载器。可自定义

// Decompiled by Jad v1.5.8e2. Copyright 2001 Pavel Kouznetsov.
// Jad home page: http://kpdus.tripod.com/jad.html
// Decompiler options: packimports(3) fieldsfirst ansi space 
// Source File Name:   SICBlockCipher.java

package org.bouncycastle.crypto.modes;

import org.bouncycastle.crypto.*;
import org.bouncycastle.crypto.params.ParametersWithIV;

public class SICBlockCipher
	implements BlockCipher
{

	private BlockCipher cipher;
	private int blockSize;
	private byte IV[];
	private byte counter[];
	private byte counterOut[];
	private boolean encrypting;

	public SICBlockCipher(BlockCipher c)
	{
		cipher = null;
		cipher = c;
		blockSize = cipher.getBlockSize();
		IV = new byte[blockSize];
		counter = new byte[blockSize];
		counterOut = new byte[blockSize];
	}

	public BlockCipher getUnderlyingCipher()
	{
		return cipher;
	}

	public void init(boolean forEncryption, CipherParameters params)
		throws IllegalArgumentException
	{
		encrypting = forEncryption;
		if (params instanceof ParametersWithIV)
		{
			ParametersWithIV ivParam = (ParametersWithIV)params;
			byte iv[] = ivParam.getIV();
			System.arraycopy(iv, 0, IV, 0, IV.length);
			reset();
			cipher.init(true, ivParam.getParameters());
		}
	}

	public String getAlgorithmName()
	{
		return (new StringBuilder()).append(cipher.getAlgorithmName()).append("/SIC").toString();
	}

	public int getBlockSize()
	{
		return cipher.getBlockSize();
	}

	public int processBlock(byte in[], int inOff, byte out[], int outOff)
		throws DataLengthException, IllegalStateException
	{
		cipher.processBlock(counter, 0, counterOut, 0);
		for (int i = 0; i < counterOut.length; i++)
			out[outOff + i] = (byte)(counterOut[i] ^ in[inOff + i]);

		int carry = 1;
		for (int i = counter.length - 1; i >= 0; i--)
		{
			int x = (counter[i] & 0xff) + carry;
			if (x > 255)
				carry = 1;
			else
				carry = 0;
			counter[i] = (byte)x;
		}

		return counter.length;
	}

	public void reset()
	{
		System.arraycopy(IV, 0, counter, 0, counter.length);
		cipher.reset();
	}
}