一个Java版的DES加密工具类，可以用来进行网络数据传输加密，保存密码的时候进行加密。

import java.security.Key;  import java.security.spec.AlgorithmParameterSpec;    import javax.crypto.Cipher;  import javax.crypto.SecretKeyFactory;  import javax.crypto.spec.DESKeySpec;  import javax.crypto.spec.IvParameterSpec;    /**   * 加密解密工具包   */  public class CyptoUtils {     public static final String ALGORITHM_DES = "DES/CBC/PKCS5Padding";         /**       * DES算法，加密       *       * @param data 待加密字符串       * @param key  加密私钥，长度不能够小于8位       * @return 加密后的字节数组，一般结合Base64编码使用       * @throws InvalidAlgorithmParameterException        * @throws Exception        */      public static String encode(String key,String data) {       if(data == null)        return null;       try{        DESKeySpec dks = new DESKeySpec(key.getBytes());              SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("DES");           //key的长度不能够小于8位字节           Key secretKey = keyFactory.generateSecret(dks);           Cipher cipher = Cipher.getInstance(ALGORITHM_DES);           IvParameterSpec iv = new IvParameterSpec("12345678".getBytes());           AlgorithmParameterSpec paramSpec = iv;           cipher.init(Cipher.ENCRYPT_MODE, secretKey,paramSpec);                      byte[] bytes = cipher.doFinal(data.getBytes());                       return byte2hex(bytes);       }catch(Exception e){        e.printStackTrace();        return data;       }      }        /**       * DES算法，解密       *       * @param data 待解密字符串       * @param key  解密私钥，长度不能够小于8位       * @return 解密后的字节数组       * @throws Exception 异常       */      public static String decode(String key,String data) {       if(data == null)        return null;          try {        DESKeySpec dks = new DESKeySpec(key.getBytes());        SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("DES");              //key的长度不能够小于8位字节              Key secretKey = keyFactory.generateSecret(dks);              Cipher cipher = Cipher.getInstance(ALGORITHM_DES);              IvParameterSpec iv = new IvParameterSpec("12345678".getBytes());              AlgorithmParameterSpec paramSpec = iv;              cipher.init(Cipher.DECRYPT_MODE, secretKey, paramSpec);              return new String(cipher.doFinal(hex2byte(data.getBytes())));          } catch (Exception e){        e.printStackTrace();        return data;          }      }     /**    * 二行制转字符串    * @param b    * @return    */      private static String byte2hex(byte[] b) {    StringBuilder hs = new StringBuilder();    String stmp;    for (int n = 0; b!=null && n < b.length; n++) {     stmp = Integer.toHexString(b[n] & 0XFF);     if (stmp.length() == 1)      hs.append('0');     hs.append(stmp);    }    return hs.toString().toUpperCase();   }            private static byte[] hex2byte(byte[] b) {          if((b.length%2)!=0)              throw new IllegalArgumentException();    byte[] b2 = new byte[b.length/2];    for (int n = 0; n < b.length; n+=2) {        String item = new String(b,n,2);        b2[n/2] = (byte)Integer.parseInt(item,16);    }          return b2;      }        }