java字符串加密解密

java字符串加密解密

(2012-02-21 17:22:31)

java字符串加密解密

java字符串加密解密  

try {
                 String test = "[e-mail]";
                 EncryptionDecryption des = new EncryptionDecryption("tourhb");// 自定义密钥
                 System.out.println("加密前的字符：" + test);
                 System.out.println("加密后的字符：" + des.encrypt(test));
                 System.out.println("解密后的字符：" + des.decrypt(des.encrypt(test)));

                 System.out.println("解密后的字符："
                         + des.decrypt("fe14c7c41f7d2a94b07d7928b21346e7"));

             } catch (Exception e) {
                 e.printStackTrace();
             }

 下面是加密解密类的源码

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

 import javax.crypto.Cipher;

 public class EncryptionDecryption {

     private static String strDefaultKey = "tourhb";

     
     private Cipher encryptCipher = null;

     
     private Cipher decryptCipher = null;

     
     public static String byteArr2HexStr(byte[] arrB) throws Exception {
         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();
     }

     
     public static byte[] hexStr2ByteArr(String strIn) throws Exception {
         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;
     }

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

     
     public EncryptionDecryption(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 {
         try {
             return new String(decrypt(hexStr2ByteArr(strIn)));
         } catch (Exception e) {
             return "";
         }
     }

     
     private Key getKey(byte[] arrBTmp) throws Exception {
         // 创建一个空的8位字节数组（默认值为0）
         byte[] arrB = new byte[8];

         // 将原始字节数组转换为8位
         for (int i = 0; i < arrBTmp.length && i < arrB.length; i++) {
             arrB[i] = arrBTmp[i];
         }

         // 生成密钥
         Key key = new javax.crypto.spec.SecretKeySpec(arrB, "DES");

         return key;
     }
 
 }