JAVA加密解密

1package com.resoft.util;

  3import java.io.UnsupportedEncodingException;

  4import java.security.InvalidKeyException;

  5import java.security.MessageDigest;

  6import java.security.NoSuchAlgorithmException;

  7import java.security.SecureRandom;

  8import java.security.spec.InvalidKeySpecException;

 10import javax.crypto.BadPaddingException;

 11import javax.crypto.Cipher;

 12import javax.crypto.IllegalBlockSizeException;

 13import javax.crypto.NoSuchPaddingException;

 14import javax.crypto.SecretKey;

 15import javax.crypto.SecretKeyFactory;

 16import javax.crypto.spec.DESKeySpec;

 18import sun.misc.BASE64Encoder;

 20/** *//**
* 安全加密类
* 
* @date 2007-10-31
* @author yayagepei
* 
*/

 27public class SecurityEncode {

   /** *//**
    * MD5方式加密字符串
    * 
    * @param str
    *            要加密的字符串
    * @return 加密后的字符串
    * @throws NoSuchAlgorithmException
    * @throws UnsupportedEncodingException
    * @author yayagepei
    * @date 2007-10-31
    * @comment 程序的价值体现在两个方面:它现在的价值,它未来的价值
    */
   public static String encoderByMd5(String str)
           throws NoSuchAlgorithmException, UnsupportedEncodingException {
       // 确定计算方法
       MessageDigest md5 = MessageDigest.getInstance("MD5");
       BASE64Encoder base64en = new BASE64Encoder();
       // 加密后的字符串
       String newstr = base64en.encode(md5.digest(str.getBytes("utf-8")));
       return newstr;
   }

   /** *//**
    * DES加解密
    * 
    * @param plainText
    *            要处理的byte[]
    * @param key
    *            密钥
    * @param mode
    *            模式
    * @return
    * @throws InvalidKeyException
    * @throws InvalidKeySpecException
    * @throws NoSuchAlgorithmException
    * @throws NoSuchPaddingException
    * @throws BadPaddingException
    * @throws IllegalBlockSizeException
    * @throws UnsupportedEncodingException
    * @author yayagepei
    * @date 2008-10-8
    */
   private static byte[] coderByDES(byte[] plainText, String key, int mode)
           throws InvalidKeyException, InvalidKeySpecException,
           NoSuchAlgorithmException, NoSuchPaddingException,
           BadPaddingException, IllegalBlockSizeException,
           UnsupportedEncodingException {
       SecureRandom sr = new SecureRandom();
       byte[] resultKey = makeKey(key);
       DESKeySpec desSpec = new DESKeySpec(resultKey);
       SecretKey secretKey = SecretKeyFactory.getInstance("DES")
               .generateSecret(desSpec);
       Cipher cipher = Cipher.getInstance("DES");
       cipher.init(mode, secretKey, sr);
       return cipher.doFinal(plainText);
   }

   /** *//**
    * 生产8位的key
    * 
    * @param key
    *            字符串形式
    * @return
    * @throws UnsupportedEncodingException
    * @author yayagepei
    * @date 2008-10-8
    */
   private static byte[] makeKey(String key)
           throws UnsupportedEncodingException {
       byte[] keyByte = new byte[8];
       byte[] keyResult = key.getBytes("UTF-8");
       for (int i = 0; i < keyResult.length && i < keyByte.length; i++) {
           keyByte[i] = keyResult[i];
       }
       return keyByte;
   }

   /** *//**
    * DES加密
    * 
    * @param plainText
    *            明文
    * @param key
    *            密钥
    * @return
    * @author yayagepei
    * @date 2008-10-8
    */
   public static String encoderByDES(String plainText, String key) {
       try {
           byte[] result = coderByDES(plainText.getBytes("UTF-8"), key,
                   Cipher.ENCRYPT_MODE);
           return byteArr2HexStr(result);
       } catch (Exception ex) {
           ex.printStackTrace();
           return "";
       }
   }

   /** *//**
    * DES解密
    * 
    * @param secretText
    *            密文
    * @param key
    *            密钥
    * @return
    * @author yayagepei
    * @date 2008-10-8
    */
   public static String decoderByDES(String secretText, String key) {
       try {
           byte[] result = coderByDES(hexStr2ByteArr(secretText), key,
                   Cipher.DECRYPT_MODE);
           return new String(result, "UTF-8");
       } catch (Exception ex) {
           ex.printStackTrace();
           return "";
       }
   }

   /** *//**
    * 将byte数组转换为表示16进制值的字符串， 如：byte[]{8,18}转换为：0813， 和public static byte[]
    * hexStr2ByteArr(String strIn) 互为可逆的转换过程
    * 
    * @param arrB
    *            需要转换的byte数组
    * @return 转换后的字符串
    */
   private static String byteArr2HexStr(byte[] arrB){
       int iLen = arrB.length;
       // 每个byte用两个字符才能表示，所以字符串的长度是数组长度的两倍
       StringBuffer sb = new StringBuffer(iLen * 2);
       for (int i = 0; i < iLen; i++) {
           int intTmp = arrB[i];
           // 把负数转换为正数
           while (intTmp < 0) {
               intTmp = intTmp + 256;
           }
           // 小于0F的数需要在前面补0
           if (intTmp < 16) {
               sb.append("0");
           }
           sb.append(Integer.toString(intTmp, 16));
       }
       return sb.toString();
   }

   /** *//**
    * 将表示16进制值的字符串转换为byte数组， 和public static String byteArr2HexStr(byte[] arrB)
    * 互为可逆的转换过程
    * 
    * @param strIn
    *            需要转换的字符串
    * @return 转换后的byte数组
    * @throws NumberFormatException
    */
   private static byte[] hexStr2ByteArr(String strIn)
           throws NumberFormatException {
       byte[] arrB = strIn.getBytes();
       int iLen = arrB.length;
       // 两个字符表示一个字节，所以字节数组长度是字符串长度除以2
       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;
   }

199}

200