DESUtil.java 4.78 KB
package com.bjivt.util.symmetric;
import java.security.Key;
import java.security.SecureRandom;

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

import sun.misc.BASE64Decoder;
import sun.misc.BASE64Encoder;
   /**
    * 对称加密工具类
    * @author zsf
    *
    */
public class DESUtil {
	Key key;  
	  
    public DESUtil() {  
  
    }  
  
    public DESUtil(String str) {  
        setKey(str); // 生成密匙  
    }  
  
    public Key getKey() {  
        return key;  
    }  
  
    public void setKey(Key key) {  
        this.key = key;  
    }  
    private static final String secretKey="JiMeiJiaJuO@O";
    /** 
     * 根据参数生成 KEY   
    */  
    public void setKey (String strKey) {  
        try {  
            KeyGenerator _generator = KeyGenerator.getInstance("DES");  
            //防止linux下 随机生成key   
            SecureRandom secureRandom = SecureRandom.getInstance("SHA1PRNG" );  
            secureRandom.setSeed(strKey.getBytes());  
              
            _generator.init(56,secureRandom);  
            this.key = _generator.generateKey();  
            _generator = null;  
        } catch (Exception e) {  
            throw new RuntimeException(  
                    "Error initializing SqlMap class. Cause: " + e);  
        }  
    } 
  
    /** 
     * 加密 String 明文输入 ,String 密文输出 
     */  
    public String encryptStr(String strMing) {  
        byte[] byteMi = null;  
        byte[] byteMing = null;  
        String strMi = "";  
        BASE64Encoder base64en = new BASE64Encoder();  
        setKey(secretKey); // 生成密匙  
        try {  
            byteMing = strMing.getBytes("UTF8");  
            byteMi = this.encryptByte(byteMing);  
            strMi = base64en.encode(byteMi);  
        } catch (Exception e) {  
            throw new RuntimeException(  
                    "Error initializing SqlMap class. Cause: " + e);  
        } finally {  
            base64en = null;  
            byteMing = null;  
            byteMi = null;  
        }  
        return strMi;  
    }  
  
    /** 
     * 解密 以 String 密文输入 ,String 明文输出 
     * 
     * @param strMi 
     * @return 
     */  
    public String decryptStr(String strMi) {  
        BASE64Decoder base64De = new BASE64Decoder();  
        byte[] byteMing = null;  
        byte[] byteMi = null;  
        String strMing = "";  
        setKey(secretKey); // 生成密匙  
        try {  
            byteMi = base64De.decodeBuffer(strMi);  
            byteMing = this.decryptByte(byteMi);  
            strMing = new String(byteMing, "UTF8");  
        } catch (Exception e) {  
            throw new RuntimeException(  
                    "Error initializing SqlMap class. Cause: " + e);  
        } finally {  
            base64De = null;  
            byteMing = null;  
            byteMi = null;  
        }  
        return strMing;  
    }  
 
    /** 
     * 加密以 byte[] 明文输入 ,byte[] 密文输出 
     * 
     * @param byteS 
     * @return 
     */  
    private byte[] encryptByte(byte[] byteS) {  
        byte[] byteFina = null;  
        Cipher cipher;  
        try {  
            cipher = Cipher.getInstance("DES/ECB/PKCS5Padding");  
            cipher.init(Cipher.ENCRYPT_MODE, key);  
            byteFina = cipher.doFinal(byteS);  
        } catch (Exception e) {  
            throw new RuntimeException(  
                    "Error initializing SqlMap class. Cause: " + e);  
        } finally {  
            cipher = null;  
        }  
        return byteFina;  
    }  
  
    /** 
     * 解密以 byte[] 密文输入 , 以 byte[] 明文输出 
     * 
     * @param byteD 
     * @return 
     */  
    private byte[] decryptByte(byte[] byteD) {  
        Cipher cipher;  
        byte[] byteFina = null;  
        try {  
            cipher = Cipher.getInstance("DES/ECB/PKCS5Padding");  
            cipher.init(Cipher.DECRYPT_MODE, key);  
            byteFina = cipher.doFinal(byteD);  
        } catch (Exception e) {  
            throw new RuntimeException(  
                    "Error initializing SqlMap class. Cause: " + e);  
        } finally {  
            cipher = null;  
        }  
        return byteFina;  
    }  
   
    public static void main(String[] args) throws Exception {  
        DESUtil des = new DESUtil();   
        String str1 = "李大霄";  
        // DES 加密字符串  
        String str2 = des.encryptStr(str1);  
        // DES 解密字符串  
        String deStr = des.decryptStr(str2);  
        System.out.println(" 加密前: " + str1);  
        System.out.println(" 加密后: " + str2);  
        System.out.println(" 加密后长度: " + str2.length());  
        System.out.println(" 解密后: " + deStr); 
        System.out.println("---------------------"); 
    }  
}