Android AES加密算法，现在实际上

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/article/4183682.html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