desalgorithm.java

来自「对称和非对称加密」· Java 代码 · 共 223 行

package com.dmgc.security.cipher.symmetic.des;

import com.dmgc.security.cipher.util.*;

import java.security.InvalidKeyException;

import java.io.*;

/**
 * <p>Title: DMGC SECURITY CIPHER LIB</p>
 * <p>Description: 上海信宁科技有限公司 安全密码库(JAVA version)</p>
 * <p>Copyright: Copyright (c) 2003</p>
 * <p>Company: 上海信宁科技有限公司</p>
 * 本类主要实现DES算法对文件的加解密,文件基本没有扩张
 * @author 陆荣幸  周渊   潘勇
 * @version 1.0
 */

public class DESAlgorithm
    extends DESCore {
  /**
   * 构造函数
   */
  public DESAlgorithm() {
  }

  /**
   * DES加密
   * @param inFile 输入文件
   * @param outFile 输出文件
   * @param keys 密钥 字符串 十六进制形式
   * @throws FileNotFoundException 文件没有找到
   * @throws InvalidKeyException  密钥不正确
   * @throws IOException 输入输出异常
   * @throws java.lang.Exception  其它异常
   */
  public void Encrypt(String inFile, String outFile, String keys) throws
      FileNotFoundException, InvalidKeyException, IOException, Exception {
    FileInputStream fInput = null;
    FileOutputStream fOutput = null;
    //
    byte[] keyBytes = DESKeyGenerator.HexStringToByte(keys);

    try {
      //  输入文件
      fInput = new FileInputStream(inFile);
      //  输出文件
      fOutput = new FileOutputStream(outFile);
      //  输入文件的字节总长度
      int byteLength = fInput.available();
      //  剩余字节
      int padLength = 8 - byteLength % 8;
      //
      byte[] c = new byte[8];
      //
      byte[] oo = new byte[8];
      //
      byte[] first7 = DmgcMpInteger.getRandomByteArray(7);
      //
      System.arraycopy(first7, 0, c, 0, 7);
      //
      byte PadCount = (byte) padLength;
      //
      c[7] = PadCount;
      // 文件头生成
      DESSecretKey key0 = new DESSecretKey(keyBytes);
      //加密初始化
      coreInit(key0, false);
      //加密
      coreCrypt(c, 0, oo, 0);
      //写文件
      fOutput.write(oo, 0, 8);
      //
      if (padLength != 0) {
        byte[] pad = DmgcMpInteger.getRandomByteArray(padLength);
        //
        System.arraycopy(pad, 0, c, 0, padLength);
      }

      //
      byte[] firstbuffer = new byte[8 - padLength];
      //
      int bufferLength = fInput.read(firstbuffer);
      //
      if (bufferLength != (8 - padLength)) {
        throw new Exception("Error");
      }
      //
      System.arraycopy(firstbuffer, 0, c, padLength, 8 - padLength);
      //加密
      coreCrypt(c, 0, oo, 0);
      //写文件
      fOutput.write(oo, 0, 8);
      //
      byte[] buffer = new byte[8192];
      //
      while ( (bufferLength = fInput.read(buffer)) != -1) {
        for (int i = 0; i < bufferLength; i = i + 8) {
          System.arraycopy(buffer, i, c, 0, 8);
          coreCrypt(c, 0, oo, 0);
          fOutput.write(oo, 0, 8);

        }
      }
      //
      fInput.close();
      fOutput.close();
    }
    catch (FileNotFoundException ex) {
      ex.printStackTrace();
      throw new FileNotFoundException("File not found exception");
    }
    catch (InvalidKeyException ex) {
      ex.printStackTrace();
      throw new InvalidKeyException("Invalid key exception");
    }
    catch (IOException ex) {
      ex.printStackTrace();
      throw new IOException("IO Exception");
    }
    catch (Exception ex) {
      ex.printStackTrace();
      throw new Exception("Encryption Exception");
    }

  }

  /**
   * DES解密
   * @param inFile 输入文件
   * @param outFile 输出文件
   * @param keys 密钥 字符串  十六进制形式
   * @throws FileNotFoundException 文件没有找到
   * @throws InvalidKeyException  密钥不正确
   * @throws IOException 输入输出异常
   * @throws java.lang.Exception  其它异常
   */
  public void Decrypt(String inFile, String outFile, String keys) throws
      FileNotFoundException, InvalidKeyException, IOException, Exception {

    FileInputStream fInput = null;
    FileOutputStream fOutput = null;
   // byte[] keyBytes = keys.getBytes();

    byte[] keyBytes = DESKeyGenerator.HexStringToByte(keys);

    try {
      //  输入文件
      fInput = new FileInputStream(inFile);
      //  输出文件
      fOutput = new FileOutputStream(outFile);
      //  剩余字节
      int padLength = 0;
      //
      byte[] c = new byte[8];
      //
      byte[] oo = new byte[8];

      // 文件头生成
      DESSecretKey key0 = new DESSecretKey(keyBytes);
      //加密初始化
      coreInit(key0, true);
      //
      int bufferLength = 0;
      //
      byte[] buffer = new byte[8192];
      //
      boolean token = false;
      //
      int offset = 0;
      //
      while ( (bufferLength = fInput.read(buffer)) != -1) {
        for (int i = 0; i < bufferLength; i = i + 8) {
          System.arraycopy(buffer, i, c, 0, 8);
          coreCrypt(c, 0, oo, 0);
          if (token == true) {
            fOutput.write(oo, offset, 8 - offset);
            if (offset != 0) {
              offset = 0;
            }
          }
          else {
            offset = oo[7];
            token = true;
          }

        }
      }
      //
      fInput.close();
      fOutput.close();

    }

    catch (FileNotFoundException ex) {
      ex.printStackTrace();
      throw new FileNotFoundException("File not found exception");
    }
    catch (InvalidKeyException ex) {
      ex.printStackTrace();
      throw new InvalidKeyException("Invalid key exception");
    }
    catch (IOException ex) {
      ex.printStackTrace();
      throw new IOException("IO Exception");
    }
    catch (Exception ex) {
      ex.printStackTrace();
      throw new Exception("Encryption Exception");
    }

  }

////////////////////////////////////////////////////////////////////////////////
  /**
   * 用于测试
   * @param args
   */
  public static void main(String[] args) {
    DESAlgorithm DESAlgorithm1 = new DESAlgorithm();
  }

}