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FileEncryptor.java：源码内容
							package org.infosecurity.cryptography;
/**
 * <p>Title: DES_CBC文件加密器 </p>
 * <p>Description: DES_CBC文件加密器 </p>
 * <p>Copyright: Copyright (c) 2003</p>
 * <p>Company: 中信信息安全组织(CISO)</p>
 * @author 张荣华
 * @version 1.0.2003.1028
 */
import org.infosecurity.cryptography.*;
import java.io.*;
public class FileEncryptor extends DES {
    //=========================================================
    // 定义错误类型,以有意义的常量代替数字
    public final static int S_OK        =  1; /* 成功         */
    public final static int S_IV_ERROR  = -1; /* 初始化向量出错 */
    public final static int S_ENC_ERROR = -2; /* 加密错误      */
    public final static int S_DEC_ERROR = -3; /* 解密错误      */
    /**
     * 构造函数
     * @param pwd 密码 (8 个字节)
     */
    public FileEncryptor(byte[] pwd) {
        super(pwd);
    }
    /**
     * CBC模式的加密
     * @param iv  初始向量
     * @param in  输入数据
     * @param out 输出数据
     * @return 输出数据的长度
     */
    public int EncryptCBC(byte[] iv,InputStream in,OutputStream out)
            throws IOException
    {
        // =========================================================
        // 定义变量
        int out_length    = 0;              /* 输出长度           */
        int block_count   = 0;              /* 数据块数           */
        int return_flag   =-2;              /* 返回字节数         */
        byte remaider     = 0;              /* 剩余字节数         */
        byte[] IV         = new byte[8];    /* 初始向量           */
        byte[] bTemp      = new byte[8];    /* 临时缓冲区         */
        byte[] out_block  = new byte[8];    /* 输出内容           */
        byte[] last_block = new byte[8];    /* 最后一个数据块      */
        // =========================================================
        // 合法性检查
        if(iv == null||iv.length!=8)
            return S_IV_ERROR;
        // =========================================================
        // 处理IV
        out_block = encrypt(iv);
        if(out_block == null || out_block.length == 0)
            return S_ENC_ERROR;
        out.write(out_block,0,8);
        out.flush();
        System.arraycopy(out_block,0,IV, 0,8);
        out_length += 8;
        // =========================================================
        // 处理输入的数据
        return_flag=in.read(bTemp,0,8);
        while(return_flag==8)
        {
            for(int j = 0;j < 8;j++)
            {
                IV[j]^=bTemp[j];
                //MyDebug.out("in["+j+"]="+bTemp[j]);      /* 调试信息 */
            }
            out_length += 8;
            out_block = encrypt(IV);
            if(out_block == null || out_block.length==0)
                return S_ENC_ERROR;
            out.write(out_block,0,8);
            out.flush();
            System.arraycopy(out_block,0,IV,0,8);
            out_block = null;
            return_flag=in.read(bTemp,0,8);
        }
        // =========================================================
        // 处理输入数据最后一个数据块
        byte value=0;
        if(return_flag>0)
        {
            value = (byte)(8 - return_flag);
            System.arraycopy(bTemp,0,last_block,0,return_flag);/* 如果有数据,将它复制过来 */
            for(int i=return_flag;i<8;i++)last_block[i]=value; /* 进行填充              */
        }
        else
        {
            value = (byte)8;
            for(int i=0;i<8;i++)last_block[i]=(byte)8;        /* 进行填充              */
        }
        for(int j = 0;j < 8;j++)
            IV[j]^=last_block[j];
        out_length += 8;
        out_block = encrypt(IV);
        if(out_block == null || out_block.length==0)
            return S_ENC_ERROR;
        out.write(out_block,0,8);
        out.flush();
//        out.close();
//        in.close();
        return out_length;
    }
    /**
     * CBC模式的解密
     * @param in  输入数据
     * @param out 输出数据
     * @return 输出数据的长度
     */
    public int DecryptCBC(InputStream in,OutputStream out) throws IOException
    {
        // =========================================================
        // 定义变量
        int out_length    = 0,cur_pos = 0;  /* 输出长度与当前位置 */
        int block_count   = 0;              /* 数据块数           */
        byte remaider     = 0;              /* 剩余字节数         */
        int return_flag   =-2;              /* 返回字节数         */
        byte[] IV         = new byte[8];    /* 初始化向量         */
        byte[] bTemp      = new byte[8];    /* 临时缓冲区         */
        byte[] out_block  = new byte[8];    /* 输出内容           */
        byte[] last_block = new byte[8];    /* 最后一个数据块      */
        // =========================================================
        // 处理IV
        block_count = in.available()/8;
        return_flag = in.read(IV,0,8);
        // =========================================================
        // 处理输入的数据
        return_flag = in.read(bTemp,0,8);
        for(int i = 0 ; i < block_count-1&&return_flag>0;i++) /* -1的原因是要去除第一块 */
        {
            out_block = decrypt(bTemp);
            if(out_block == null || out_block.length==0)
                return S_DEC_ERROR;
            for(int j = 0;j < 8;j++)
            {
                out_block[j]^=IV[j];
                //MyDebug.out("out_block["+j+"]="+out_block[j]);
                                              /* 调试信息          */
            }
            if(i==block_count-2)
            {
                byte real_count = (byte)(8 - out_block[7]);
                out_length += real_count;
                out.write(out_block,0,real_count);
            }
            else
            {
                out_length += 8;
                out.write(out_block,0,8);
            }
            out.flush();
            System.arraycopy(bTemp,0,IV,0,8);
            out_block = null;
            return_flag = in.read(bTemp,0,8);
        }
        return out_length;
    }
    public static void main(String args[])
    {
        FileInputStream  fis = null;
        FileOutputStream fos = null;
        try {
            FileEncryptor fe = new FileEncryptor("12345678".getBytes());
            fis = new FileInputStream("E:\JavaProj\temp\ciphertext.txt");
            fos = new FileOutputStream("E:\JavaProj\temp\result.txt");
            fe.DecryptCBC(fis,fos);
            fis.close();
            fos.close();
        }
        catch (IOException ex) {
            MyDebug.out("Dec 出错了!");
        }
    }
}

						