昨天，老板让我来看看android加密算法。于是在网上找了找，发现AES加密算法。（当然，MD5,BASE64什么http://snowolf.iteye.com/blog/379860这篇文章列举了非常多。可是基本都是j2se平台的。android平台不一定支持，可是AES算法Android是自带了包的，从官方的http://developer.android.com/reference/javax/crypto/Cipher.html能够看到。

）

AES加密算法是什么？大家能够自己去google，专家级程序猿写好包，project人员会用即可了。

这个样例事实上是来自http://www.tutorials-android.com/learn/How_to_encrypt_and_decrypt_strings.rhtml。

src文件夹主文件：

package com.qq;

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;

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 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. */

    @Override

    public void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.main);

        String masterPassword = "a";

        String originalText = "0123456789";

        byte[] text = new byte[]{'0','1','2','3','4','5','6','7','8','9'};

        byte[] password = new byte[]{'a'};

        try {

    		String encryptingCode = SimpleCrypto.encrypt(masterPassword,originalText);

//    		System.out.println("加密结果为 " + encryptingCode);

    		Log.i("加密结果为 ",encryptingCode);

    		String decryptingCode = SimpleCrypto.decrypt(masterPassword, encryptingCode);

    		System.out.println("解密结果为 " + decryptingCode);

    		Log.i("解密结果",decryptingCode);

    	   } catch (Exception e) {

    		// TODO Auto-generated catch block

    		e.printStackTrace();

    }

    }

}

布局文件main.xml和配置文件AndroidManifest.xml默认就好了。

最后结果在Log里面看，利用adb logcat > d:\1.txt定位到D盘的1.txt文件。然后用记事本打开就，查找”加密结果为“就能够看到了：

执行结果（从log日志中看到的）：

I/加密结果 (  190): BFB77D8F1E1EE9D5E252926A12659DE8

I/解密结果(  190): 0123456789