android des 加密

对称 ， 没有随机码（或者是使用系统内部的随机码），加密内容一对一，不会随时改变；

加密key byte lengh = 8 ，不可加长或者变短， 易碰撞破解；

比较简单 ，性能高点；

package widget;

import javax.crypto.Cipher;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;

import android.util.Base64;

public class CipherDes {  
    private static final String Algorithm = "DES";  //定义 加密算法,可用 DES,DESede,Blowfish
 
    // 加密字符串
    public  String encryptMode(byte[] keybyte, String input) {
    	checkKey(keybyte);
    	
        try { // 生成密钥
            SecretKey deskey = new SecretKeySpec(keybyte, Algorithm); // 加密
            Cipher c1 = Cipher.getInstance(Algorithm);
            c1.init(Cipher.ENCRYPT_MODE, deskey);
            byte[] results = c1.doFinal(input.getBytes("utf-8"));
            String encrypted = Base64.encodeToString(results, Base64.DEFAULT);
            return encrypted;
        } catch (java.security.NoSuchAlgorithmException e1) {
            e1.printStackTrace();
        } catch (javax.crypto.NoSuchPaddingException e2) {
            e2.printStackTrace();
        } catch (java.lang.Exception e3) {
            e3.printStackTrace();
        }
        return null;
    }
 
    // 解密字符串
    public  String decryptMode(byte[] keybyte, String encrypted) {
    	checkKey(keybyte);
    	
        try { // 生成密钥
        	byte[] src = Base64.decode(encrypted, Base64.DEFAULT);
            SecretKey deskey = new SecretKeySpec(keybyte, Algorithm); // 解密
            Cipher c1 = Cipher.getInstance(Algorithm);
            c1.init(Cipher.DECRYPT_MODE, deskey);
            return new String(c1.doFinal(src),"utf-8");
        } catch (java.security.NoSuchAlgorithmException e1) {
            e1.printStackTrace();
        } catch (javax.crypto.NoSuchPaddingException e2) {
            e2.printStackTrace();
        } catch (java.lang.Exception e3) {
            e3.printStackTrace();
        }
        return null;
    }
    
    private void checkKey(byte key[]){
    	if(key.length != 8)
    		throw new IllegalArgumentException("key byte lenght should = 8");
    }
}