Android AES加密算法及其实现

这个例子是来自http://www.tutorials-android.com/learn/How_to_encrypt_and_decrypt_strings.rhtml。

package com.vzo.eightpartycall.activity;

import java.security.SecureRandom;

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

import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.view.Window;
import android.widget.TextView;

import com.vzo.eightpartycall.R;

public class SimpleCrypto extends Activity {
     public static String encrypt(String seed, String cleartext) throws Exception {    
            byte[] rawKey = getRawKey(seed.getBytes());    
            byte[] result = encrypt(rawKey, cleartext.getBytes());    
            return toHex(result);    
        }    
            
        public static String decrypt(String seed, String encrypted) throws Exception {    
            byte[] rawKey = getRawKey(seed.getBytes());    
            byte[] enc = toByte(encrypted);    
            byte[] result = decrypt(rawKey, enc);
//          return  BinstrToStr(new String(result));
            return new String(result);    
        }    
       
        private static byte[] getRawKey(byte[] seed) throws Exception {    
            KeyGenerator kgen = KeyGenerator.getInstance("AES");    
            SecureRandom sr = SecureRandom.getInstance("SHA1PRNG");    
            sr.setSeed(seed);    
            kgen.init(128, sr); // 192 and 256 bits may not be available    
            SecretKey skey = kgen.generateKey();    
            byte[] raw = skey.getEncoded();    
            return raw;    
        }    
       
            
        private static byte[] encrypt(byte[] raw, byte[] clear) throws Exception {    
            SecretKeySpec skeySpec = new SecretKeySpec(raw, "AES");    
            Cipher cipher = Cipher.getInstance("AES");    
            cipher.init(Cipher.ENCRYPT_MODE, skeySpec);    
            byte[] encrypted = cipher.doFinal(clear);    
            return encrypted;    
        }    
       
        private static byte[] decrypt(byte[] raw, byte[] encrypted) throws Exception {    
            SecretKeySpec skeySpec = new SecretKeySpec(raw, "AES");    
            Cipher cipher = Cipher.getInstance("AES");    
            cipher.init(Cipher.DECRYPT_MODE, skeySpec);    
            byte[] decrypted = cipher.doFinal(encrypted);    
            return decrypted;    
        }    
       
        public static String toHex(String txt) {    
            return toHex(txt.getBytes());    
        }    
        public static String fromHex(String hex) {    
            return new String(toByte(hex));    
        }    
            
        public static byte[] toByte(String hexString) {    
            int len = hexString.length()/2;    
            byte[] result = new byte[len];    
            for (int i = 0; i < len; i++)    
                result[i] = Integer.valueOf(hexString.substring(2*i, 2*i+2), 16).byteValue();    
            return result;    
        }    
       
        public static String toHex(byte[] buf) {    
            if (buf == null)    
                return "";    
            StringBuffer result = new StringBuffer(2*buf.length);    
            for (int i = 0; i < buf.length; i++) {    
                appendHex(result, buf[i]);    
            }    
            return result.toString();    
        }    
        private final static String HEX = "0123456789abcdef";    
        private static void appendHex(StringBuffer sb, byte b) {    
            sb.append(HEX.charAt((b>>4)&0x0f)).append(HEX.charAt(b&0x0f));    
        }
    /** Called when the activity is first created. */
        
        private TextView tv1, tv2, tv3, tv4;
 @Override
 public void onCreate(Bundle savedInstanceState) {
     super.onCreate(savedInstanceState);
     requestWindowFeature(Window.FEATURE_NO_TITLE);
     setContentView(R.layout.main);
     tv1 = (TextView) findViewById(R.id.textView1);
     tv2 = (TextView) findViewById(R.id.textView2);
     tv3 = (TextView) findViewById(R.id.textView3);
     tv4 = (TextView) findViewById(R.id.textView4);
     
     
     
     
     String masterPassword = "newbft12345stock";
     tv1.setText("密钥密码: "+masterPassword);
     String originalText = "18611111111";
     tv2.setText("加密号码: "+originalText);
     
     byte[] text = new byte[]{'1','8','6','1','1','1','1','1','1','1'};
//     byte[] password = new byte[]{'n','e','w','b','f','t','1','2','3','4','5','s','t','o','c','k'};
     byte[] password = masterPassword.getBytes();
     try {
         String encryptingCode = SimpleCrypto.encrypt(masterPassword,originalText);
//         System.out.println("加密结果为 " + encryptingCode);
         Log.i("lanjianlong,加密结果为 ",encryptingCode);
         tv3.setText("加密结果: "+encryptingCode);
         
         String decryptingCode = SimpleCrypto.decrypt(masterPassword, encryptingCode);
         System.out.println("解密结果为 " + decryptingCode);
         Log.i("lanjianlong,解密结果",decryptingCode);
         tv4.setText("解密结果: "+decryptingCode);
        } catch (Exception e) {
         // TODO Auto-generated catch block
         e.printStackTrace();
 }
     
 }
 private static String BinstrToStr(String binStr) {
     String[] tempStr=StrToStrArray(binStr);
     char[] tempChar=new char[tempStr.length];
     for(int i=0;i<tempStr.length;i++) {
         tempChar[i]=BinstrToChar(tempStr[i]);
     }
     return String.valueOf(tempChar);
 }
 private static String[] StrToStrArray(String str) {
     return str.split(" ");
 }
 private static char BinstrToChar(String binStr){
     int[] temp=BinstrToIntArray(binStr);
     int sum=0;   
     for(int i=0; i<temp.length;i++){
         sum +=temp[temp.length-1-i]<<i;
     }   
     return (char)sum;
 }
 private static int[] BinstrToIntArray(String binStr) {       
     char[] temp=binStr.toCharArray();
     int[] result=new int[temp.length];   
     for(int i=0;i<temp.length;i++) {
         result[i]=temp[i]-48;
     }
     return result;
 }
 
}