Android AES密碼編譯演算法及其實現

       昨天老大叫我看看android密碼編譯演算法。於是網上找了找，找到了AES密碼編譯演算法。（當然還有MD5,BASE64什麼的http://snowolf.iteye.com/blog/379860這篇文章列舉了很多，但是基本都是j2se平台的，android平台不一定支援，但是AES演算法Android是內建了包的，從官方的http://developer.android.com/reference/javax/crypto/Cipher.html可以看到。
）

 AES密碼編譯演算法是什嗎？大家可以自己去google，專家級程式員寫好包，工程人員會用就行了。

這個例子其實是來自http://www.tutorials-android.com/learn/How_to_encrypt_and_decrypt_strings.rhtml。

src目錄主檔案：

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("加密結果為 " + encryptingCode);    Log.i("加密結果為 ",encryptingCode);    String decryptingCode = SimpleCrypto.decrypt(masterPassword, encryptingCode);    System.out.println("解密結果為 " + decryptingCode);    Log.i("解密結果",decryptingCode);       } catch (Exception e) {    // TODO Auto-generated catch block    e.printStackTrace();    }    }}

布局檔案main.xml和設定檔AndroidManifest.xml預設就好了。最後結果在Log裡面看，利用adb logcat > d:\1.txt定位到D盤的1.txt檔案，然後用記事本開啟就，尋找”加密結果為“就可以看到了：

運行結果（從log日誌中看到的）：

I/加密結果為 (  190): BFB77D8F1E1EE9D5E252926A12659DE8

I/解密結果(  190): 0123456789