两个Java加密解密例子

java 加密解密 示例：[url]http://rian.iteye.com/blog/196031[/url]

import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.security.Key;
import java.security.MessageDigest;

import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;

public class Demo {
  public static void main(String args[]) {
    String password = "administrator";
    try {
      Demo.PrivEncrypt(password,"t.obj");
    } catch (Exception e) {
      e.printStackTrace();
    }
  }

  /**
   * 
   * @param oldStr
   *            要加密的串
   * @param keyFile
   *            私有key所在的文件路径
   * @throws Exception
   */
  public static void PrivEncrypt(String oldStr,String keyFile) throws Exception {
    System.out.println("原始："+oldStr);
    byte[] plainText = oldStr.getBytes("GBK");
    Key key = getPriveKey(keyFile);
    // 获得一个私鈅加密类Cipher，ECB是加密方式，PKCS5Padding是填充方法
    Cipher cipher = Cipher.getInstance("AES/ECB/PKCS5Padding");

    cipher.init(Cipher.ENCRYPT_MODE, key);// 使用私鈅加密
    byte[] cipherText = cipher.doFinal(plainText);
    System.out.println("加密："+new String(cipherText, "UTF8"));

    cipher.init(Cipher.DECRYPT_MODE, key);// 使用私钥解密
    byte[] newPlainText = cipher.doFinal(cipherText);
    System.out.println("解密："+new String(newPlainText, "UTF8"));
  }

  // 把Key 写到文件中：生成一个私有Key对象，保存在文件中
  public static void setPriveKey(String file) {
    FileOutputStream fos;
    try {
      fos = new FileOutputStream(file);
      KeyGenerator keyGen = KeyGenerator.getInstance("DES");
      keyGen.init(128);
      Key key = keyGen.generateKey();// 生成私钥Key
      ObjectOutputStream oos = new ObjectOutputStream(fos);
      oos.writeObject(key);
      oos.close();
    } catch (Exception e1) {
      e1.printStackTrace();
    }
  }
  // 从文件中读Key：客户端可以根据管理员提供的私钥Key文件提取Key对象
  public static Key getPriveKey(String file) throws Exception {
    FileInputStream fis = new FileInputStream(file);
    ObjectInputStream ois = new ObjectInputStream(fis);
    Key key = (Key) ois.readObject();
    return key;
  }
}
/* 运行结果：
 * 原始：administrator 
 * 加密：!Y????I?? ??R;?
 * 解密：administrator
 */

DES加密、解密字符串算法:[url]http://www.icnote.com/des-encrypt/[/url]

package com.common;

import java.security.Key;
import java.security.Security;

import javax.crypto.Cipher;

public class DESPlus {
  private static String strDefaultKey = "national";
  private Cipher encryptCipher = null;
  private Cipher decryptCipher = null;

  public static String byteArr2HexStr(byte[] arrB) throws Exception {
    int iLen = arrB.length;
    StringBuffer sb = new StringBuffer(iLen * 2);
    for (int i = 0; i < iLen; i++) {
      int intTmp = arrB[i];
      while (intTmp < 0) {
        intTmp = intTmp + 256;
      }
      if (intTmp < 16) {
        sb.append("0");
      }
      sb.append(Integer.toString(intTmp, 16));
    }
    return sb.toString();
  }

  public static byte[] hexStr2ByteArr(String strIn) throws Exception {
    byte[] arrB = strIn.getBytes();
    int iLen = arrB.length;

    byte[] arrOut = new byte[iLen / 2];
    for (int i = 0; i < iLen; i = i + 2) {
      String strTmp = new String(arrB, i, 2);
      arrOut[i / 2] = (byte) Integer.parseInt(strTmp, 16);
    }
    return arrOut;
  }

  public DESPlus() throws Exception {
    this(strDefaultKey);
  }

  public DESPlus(String strKey) throws Exception {
    Security.addProvider(new com.sun.crypto.provider.SunJCE());
    Key key = getKey(strKey.getBytes());

    encryptCipher = Cipher.getInstance("DES");
    encryptCipher.init(Cipher.ENCRYPT_MODE, key);

    decryptCipher = Cipher.getInstance("DES");
    decryptCipher.init(Cipher.DECRYPT_MODE, key);
  }
  public byte[] encrypt(byte[] arrB) throws Exception {
    return encryptCipher.doFinal(arrB);
  }
  public String encrypt(String strIn) throws Exception {
    return byteArr2HexStr(encrypt(strIn.getBytes()));
  }
  public byte[] decrypt(byte[] arrB) throws Exception {
    return decryptCipher.doFinal(arrB);
  }
  public String decrypt(String strIn) throws Exception {
    return new String(decrypt(hexStr2ByteArr(strIn)));
  }
  private Key getKey(byte[] arrBTmp) throws Exception {
    byte[] arrB = new byte[8];

    for (int i = 0; i < arrBTmp.length && i < arrB.length; i++) {
      arrB[i] = arrBTmp[i];
    }
    Key key = new javax.crypto.spec.SecretKeySpec(arrB, "DES");
    return key;
  }

  public static void main(String[] args) {
    try {
      String test = "Hellow Word!";
       DESPlus des = new DESPlus("6b189a916ce2477fd55dd80903836156");
       System.out.println("str=：" + test);
       System.out.println("encrypt str=："+des.encrypt(test));
       System.out.println("decrypt str=："+des.decrypt(des.encrypt(test)));
    } catch (Exception e) {
      e.printStackTrace();
    }
  }
}