iesengine.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:   IESEngine.java

package org.bouncycastle.crypto.engines;

import java.math.BigInteger;
import org.bouncycastle.crypto.*;
import org.bouncycastle.crypto.params.*;

public class IESEngine
{

	BasicAgreement agree;
	DerivationFunction kdf;
	Mac mac;
	BufferedBlockCipher cipher;
	byte macBuf[];
	boolean forEncryption;
	CipherParameters privParam;
	CipherParameters pubParam;
	IESParameters param;

	public IESEngine(BasicAgreement agree, DerivationFunction kdf, Mac mac)
	{
		this.agree = agree;
		this.kdf = kdf;
		this.mac = mac;
		macBuf = new byte[mac.getMacSize()];
		cipher = null;
	}

	public IESEngine(BasicAgreement agree, DerivationFunction kdf, Mac mac, BufferedBlockCipher cipher)
	{
		this.agree = agree;
		this.kdf = kdf;
		this.mac = mac;
		macBuf = new byte[mac.getMacSize()];
		this.cipher = cipher;
	}

	public void init(boolean forEncryption, CipherParameters privParam, CipherParameters pubParam, CipherParameters param)
	{
		this.forEncryption = forEncryption;
		this.privParam = privParam;
		this.pubParam = pubParam;
		this.param = (IESParameters)param;
	}

	private byte[] decryptBlock(byte in_enc[], int inOff, int inLen, byte z[])
		throws InvalidCipherTextException
	{
		byte M[] = null;
		KeyParameter macKey = null;
		KDFParameters kParam = new KDFParameters(z, param.getDerivationV());
		int macKeySize = param.getMacKeySize();
		kdf.init(kParam);
		inLen -= mac.getMacSize();
		if (cipher == null)
		{
			byte buf[] = new byte[inLen + macKeySize / 8];
			M = new byte[inLen];
			kdf.generateBytes(buf, 0, buf.length);
			for (int i = 0; i != inLen; i++)
				M[i] = (byte)(in_enc[inOff + i] ^ buf[i]);

			macKey = new KeyParameter(buf, inLen, macKeySize / 8);
		} else
		{
			int cipherKeySize = ((IESWithCipherParameters)param).getCipherKeySize();
			byte buf[] = new byte[cipherKeySize / 8 + macKeySize / 8];
			cipher.init(false, new KeyParameter(buf, 0, cipherKeySize / 8));
			byte tmp[] = new byte[cipher.getOutputSize(inLen)];
			int off = cipher.processBytes(in_enc, inOff, inLen, tmp, 0);
			off += cipher.doFinal(tmp, off);
			M = new byte[off];
			System.arraycopy(tmp, 0, M, 0, off);
			macKey = new KeyParameter(buf, cipherKeySize / 8, macKeySize / 8);
		}
		byte macIV[] = param.getEncodingV();
		mac.init(macKey);
		mac.update(in_enc, inOff, inLen);
		mac.update(macIV, 0, macIV.length);
		mac.doFinal(macBuf, 0);
		inOff += inLen;
		for (int t = 0; t < macBuf.length; t++)
			if (macBuf[t] != in_enc[inOff + t])
				throw new InvalidCipherTextException("Mac codes failed to equal.");

		return M;
	}

	private byte[] encryptBlock(byte in[], int inOff, int inLen, byte z[])
		throws InvalidCipherTextException
	{
		byte C[] = null;
		KeyParameter macKey = null;
		KDFParameters kParam = new KDFParameters(z, param.getDerivationV());
		int c_text_length = 0;
		int macKeySize = param.getMacKeySize();
		kdf.init(kParam);
		if (cipher == null)
		{
			byte buf[] = new byte[inLen + macKeySize / 8];
			C = new byte[inLen + mac.getMacSize()];
			c_text_length = inLen;
			kdf.generateBytes(buf, 0, buf.length);
			for (int i = 0; i != inLen; i++)
				C[i] = (byte)(in[inOff + i] ^ buf[i]);

			macKey = new KeyParameter(buf, inLen, macKeySize / 8);
		} else
		{
			int cipherKeySize = ((IESWithCipherParameters)param).getCipherKeySize();
			byte buf[] = new byte[cipherKeySize / 8 + macKeySize / 8];
			cipher.init(true, new KeyParameter(buf, 0, cipherKeySize / 8));
			c_text_length = cipher.getOutputSize(inLen);
			C = new byte[c_text_length + mac.getMacSize()];
			int off = cipher.processBytes(in, inOff, inLen, C, 0);
			cipher.doFinal(C, off);
			macKey = new KeyParameter(buf, cipherKeySize / 8, macKeySize / 8);
		}
		byte macIV[] = param.getEncodingV();
		mac.init(macKey);
		mac.update(C, 0, c_text_length);
		mac.update(macIV, 0, macIV.length);
		mac.doFinal(C, c_text_length);
		return C;
	}

	public byte[] processBlock(byte in[], int inOff, int inLen)
		throws InvalidCipherTextException
	{
		agree.init(privParam);
		BigInteger z = agree.calculateAgreement(pubParam);
		if (forEncryption)
			return encryptBlock(in, inOff, inLen, z.toByteArray());
		else
			return decryptBlock(in, inOff, inLen, z.toByteArray());
	}
}