主要内容：DES加密算法

				package cs.lab.demo;
				
				import javax.crypto.Cipher;
				import javax.crypto.KeyGenerator;
				import javax.crypto.NoSuchPaddingException;
				import javax.crypto.SecretKey;
				
				import java.security.InvalidAlgorithmParameterException;
				import java.security.NoSuchAlgorithmException;
				import java.security.Security;
				/**
				 * DES加密的，文件中共有两个方法,加密、解密
				 * @author 
				 * @author 
				 */
				public class DES {
				    private String Algorithm = "DES";
				    private KeyGenerator keygen;
				    private SecretKey deskey;
				    private Cipher c;
				    private byte[] cipherByte;
				
				    /**
				     * 初始化 DES 实例
				     */
				    public DES() {
				          init();
				    }
				
				    public void init() {
				        Security.addProvider(new com.sun.crypto.provider.SunJCE());
				        try {
				               keygen = KeyGenerator.getInstance(Algorithm);
				               deskey = keygen.generateKey();
				               c = Cipher.getInstance("DES/CBC/NoPadding");
				               //c = Cipher.getInstance("DES/ECB/PKCS5Padding");
				         }
				         catch(NoSuchAlgorithmException ex){
				            ex.printStackTrace();
				        }
				         catch(NoSuchPaddingException ex){
				            ex.printStackTrace();
				        }
				       }
				
				    /**
				     * 对 String 进行加密
				     * @param str 要加密的数据
				     * @return 返回加密后的 byte 数组
				     */
				     public byte[] createEncryptor(String str) {
				        try {
				             c.init(Cipher.ENCRYPT_MODE, deskey);
				             cipherByte = c.doFinal(str.getBytes());
				        }
				        catch(java.security.InvalidKeyException ex){
				            ex.printStackTrace();
				        }
				        catch(javax.crypto.BadPaddingException ex){
				            ex.printStackTrace();
				        }
				        catch(javax.crypto.IllegalBlockSizeException ex){
				            ex.printStackTrace();
				        }
				        return cipherByte;
				     }
				
				    /**
				     * 对 Byte 数组进行解密
				     * @param buff 要解密的数据
				     * @return 返回加密后的 String
				     */
				     public String createDecryptor(byte[] buff) {
				        try {
				           c.init(Cipher.DECRYPT_MODE, deskey, c.getParameters() );
				           cipherByte = c.doFinal(buff);
				        }
				        catch(java.security.InvalidKeyException ex){
				            ex.printStackTrace();
				        }
				        catch(javax.crypto.BadPaddingException ex){
				            ex.printStackTrace();
				        }
				        catch(javax.crypto.IllegalBlockSizeException ex){
				            ex.printStackTrace();
				        } catch (InvalidAlgorithmParameterException e) {
				            e.printStackTrace();
				        }
				        return (new String(cipherByte));
				     }
				     public static void main(String[] args) {
				        DES des = new DES();
				        try{
				            byte[] cipher = des.createEncryptor(args[0]);
				            System.out.println("Encrypted:"+new String(cipher));//将加密的byte数组以字符串方式显示
				            String plain = des.createDecryptor(cipher);
				            System.out.println("Decrypted:"+plain);
				        }catch(Exception e){e.printStackTrace();}
				    }
				}