Android Apk加固（安全专项）

Android中的Apk的加固(加壳)原理解析和实现：http://blog.csdn.net/jiangwei0910410003/article/details/48415225

Android安全专项-Apk加固：http://blog.csdn.net/itfootball/article/details/50962459

Android APK加壳技术方案【1】 ：http://blog.csdn.net/androidsecurity/article/details/8678399

Android APK加壳技术方案【2】：http://blog.csdn.net/androidsecurity/article/details/8809542

一、序言

在上篇“Android APK加壳技术方案”（http://blog.csdn.net/jiazhijun/article/details/8678399）博文中，根据加壳数据在解壳程序Dex文件所处的位置，我提出了两种Android Dex加壳技术实现方案，本片博文将对方案1代码实现进行讲解。博友可以根据方案1的代码实现原理对方案2自行实现。

在方案1的代码实现过程中，各种不同的问题接踵出现，最初的方案也在不同问题的出现、解决过程中不断的得到调整、优化。

本文的代码实现了对整个APK包的加壳处理。加壳程序不会对源程序有任何的影响。

二、代码实现

本程序基于Android2.3代码实现，因为牵扯到系统代码的反射修改，本程序不保证在其它android版本正常工作，博友可以根据实现原理，自行实现对其它Android版本的兼容性开发。

1、 加壳程序流程及代码实现

1、加密源程序APK为解壳数据

2、把解壳数据写入解壳程序DEX文件末尾，并在文件尾部添加解壳数据的大小。

3、修改解壳程序DEX头中checksum、signature 和file_size头信息。

代码实现如下：

[java] view plain copy

package com.android.dexshell;

import java.io.ByteArrayOutputStream;

import java.io.File;

import java.io.FileInputStream;

import java.io.FileOutputStream;

import java.io.IOException;

import java.security.MessageDigest;

import java.security.NoSuchAlgorithmException;

import java.util.zip.Adler32;

public class DexShellTool {

/**

* @param args

*/

public static void main(String[] args) {

// TODO Auto-generated method stub

try {

File payloadSrcFile = new File("g:/payload.apk");

File unShellDexFile = new File("g:/unshell.dex");

byte[] payloadArray = encrpt(readFileBytes(payloadSrcFile));

byte[] unShellDexArray = readFileBytes(unShellDexFile);

int payloadLen = payloadArray.length;

int unShellDexLen = unShellDexArray.length;

int totalLen = payloadLen + unShellDexLen +4;

byte[] newdex = new byte[totalLen];

//添加解壳代码

System.arraycopy(unShellDexArray, 0, newdex, 0, unShellDexLen);

//添加加密后的解壳数据

System.arraycopy(payloadArray, 0, newdex, unShellDexLen,

payloadLen);

//添加解壳数据长度

System.arraycopy(intToByte(payloadLen), 0, newdex, totalLen-4, 4);

//修改DEX file size文件头

fixFileSizeHeader(newdex);

//修改DEX SHA1 文件头

fixSHA1Header(newdex);

//修改DEX CheckSum文件头

fixCheckSumHeader(newdex);

String str = "g:/classes.dex";

File file = new File(str);

if (!file.exists()) {

file.createNewFile();

}

FileOutputStream localFileOutputStream = new FileOutputStream(str);

localFileOutputStream.write(newdex);

localFileOutputStream.flush();

localFileOutputStream.close();

} catch (Exception e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

}

//直接返回数据，读者可以添加自己加密方法

private static byte[] encrpt(byte[] srcdata){

return srcdata;

}

private static void fixCheckSumHeader(byte[] dexBytes) {

Adler32 adler = new Adler32();

adler.update(dexBytes, 12, dexBytes.length - 12);

long value = adler.getValue();

int va = (int) value;

byte[] newcs = intToByte(va);

byte[] recs = new byte[4];

for (int i = 0; i < 4; i++) {

recs[i] = newcs[newcs.length - 1 - i];

System.out.println(Integer.toHexString(newcs[i]));

}

System.arraycopy(recs, 0, dexBytes, 8, 4);

System.out.println(Long.toHexString(value));

System.out.println();

}

public static byte[] intToByte(int number) {

byte[] b = new byte[4];

for (int i = 3; i >= 0; i--) {

b[i] = (byte) (number % 256);

number >>= 8;

}

return b;

}

private static void fixSHA1Header(byte[] dexBytes)

throws NoSuchAlgorithmException {

MessageDigest md = MessageDigest.getInstance("SHA-1");

md.update(dexBytes, 32, dexBytes.length - 32);

byte[] newdt = md.digest();

System.arraycopy(newdt, 0, dexBytes, 12, 20);

String hexstr = "";

for (int i = 0; i < newdt.length; i++) {

hexstr += Integer.toString((newdt[i] & 0xff) + 0x100, 16)

.substring(1);

}

System.out.println(hexstr);

}

private static void fixFileSizeHeader(byte[] dexBytes) {

byte[] newfs = intToByte(dexBytes.length);

System.out.println(Integer.toHexString(dexBytes.length));

byte[] refs = new byte[4];

for (int i = 0; i < 4; i++) {

refs[i] = newfs[newfs.length - 1 - i];

System.out.println(Integer.toHexString(newfs[i]));

}

System.arraycopy(refs, 0, dexBytes, 32, 4);

}

private static byte[] readFileBytes(File file) throws IOException {

byte[] arrayOfByte = new byte[1024];

ByteArrayOutputStream localByteArrayOutputStream = new ByteArrayOutputStream();

FileInputStream fis = new FileInputStream(file);

while (true) {

int i = fis.read(arrayOfByte);

if (i != -1) {

localByteArrayOutputStream.write(arrayOfByte, 0, i);

} else {

return localByteArrayOutputStream.toByteArray();

}

}

}

}

2、 解壳程序流程及代码实现

在解壳程序的开发过程中需要解决如下几个关键的技术问题：

（1）解壳代码如何能够第一时间执行？

Android程序由不同的组件构成，系统在有需要的时候启动程序组件。因此解壳程序必须在Android系统启动组件之前运行，完成对解壳数 据的解壳及APK文件的动态加载，否则会使程序出现加载类失败的异常。

Android开发者都知道Applicaiton做为整个应用的上下文，会被系统第一时间调用，这也是应用开发者程序代码的第一执行点。因此通过对 AndroidMainfest.xml的application的配置可以实现解壳代码第一时间运行。

[html] view plain copy

<application

android:icon="@drawable/ic_launcher"

android:label="@string/app_name"

android:theme="@style/AppTheme" android:name="com.android.dexunshell.ProxyApplication" >

</application>

（2）如何替换回源程序原有的Application?

当在AndroidMainfest.xml文件配置为解壳代码的Application时。源程序原有的Applicaiton将被替换，为了不影响源程序代码逻辑，我们需要 在解壳代码运行完成后，替换回源程序原有的Application对象。我们通过在AndroidMainfest.xml文件中配置原有Applicaiton类信息来达到我们 的目的。解壳程序要在运行完毕后通过创建配置的Application对象，并通过反射修改回原Application。

[html] view plain copy

<application

android:icon="@drawable/ic_launcher"

android:label="@string/app_name"

android:theme="@style/AppTheme"

android:name="com.android.dexunshell.ProxyApplication" >

<meta-data android:name="APPLICATION_CLASS_NAME" android:value="com.***.Application"/>

</application>

（3）如何通过DexClassLoader实现对apk代码的动态加载。

我们知道DexClassLoader加载的类是没有组件生命周期的，也就是说即使DexClassLoader通过对APK的动态加载完成了对组件类的加载， 当系统启动该组件时，还会出现加载类失败的异常。为什么组件类被动态加载入虚拟机，但系统却出现加载类失败呢？

通过查看Android源代码我们知道组件类的加载是由另一个ClassLoader来完成的，DexClassLoader和系统组件ClassLoader并不存在关 系，系统组件ClassLoader当然找不到由DexClassLoader加载的类，如果把系统组件ClassLoader的parent修改成DexClassLoader，我们就可 以实现对apk代码的动态加载。

（4）如何使解壳后的APK资源文件被代码动态引用。

代码默认引用的资源文件在最外层的解壳程序中，因此我们要增加系统的资源加载路径来实现对借壳后APK文件资源的加载。

解壳实现代码：

[java] view plain copy

package com.android.dexunshell;

import java.io.BufferedInputStream;

import java.io.ByteArrayInputStream;

import java.io.ByteArrayOutputStream;

import java.io.DataInputStream;

import java.io.File;

import java.io.FileInputStream;

import java.io.FileOutputStream;

import java.io.IOException;

import java.lang.ref.WeakReference;

import java.util.ArrayList;

import java.util.HashMap;

import java.util.Iterator;

import java.util.zip.ZipEntry;

import java.util.zip.ZipInputStream;

import dalvik.system.DexClassLoader;

import android.app.Application;

import android.content.pm.ApplicationInfo;

import android.content.pm.PackageManager;

import android.content.pm.PackageManager.NameNotFoundException;

import android.os.Bundle;

public class ProxyApplication extends Application {

private static final String appkey = "APPLICATION_CLASS_NAME";

private String apkFileName;

private String odexPath;

private String libPath;

protected void attachBaseContext(Context base) {

super.attachBaseContext(base);

try {

File odex = this.getDir("payload_odex", MODE_PRIVATE);

File libs = this.getDir("payload_lib", MODE_PRIVATE);

odexPath = odex.getAbsolutePath();

libPath = libs.getAbsolutePath();

apkFileName = odex.getAbsolutePath() + "/payload.apk";

File dexFile = new File(apkFileName);

if (!dexFile.exists())

dexFile.createNewFile();

// 读取程序classes.dex文件

byte[] dexdata = this.readDexFileFromApk();

// 分离出解壳后的apk文件已用于动态加载

this.splitPayLoadFromDex(dexdata);

// 配置动态加载环境

Object currentActivityThread = RefInvoke.invokeStaticMethod(

"android.app.ActivityThread", "currentActivityThread",

new Class[] {}, new Object[] {});

String packageName = this.getPackageName();

HashMap mPackages = (HashMap) RefInvoke.getFieldOjbect(

"android.app.ActivityThread", currentActivityThread,

"mPackages");

WeakReference wr = (WeakReference) mPackages.get(packageName);

DexClassLoader dLoader = new DexClassLoader(apkFileName, odexPath,

libPath, (ClassLoader) RefInvoke.getFieldOjbect(

"android.app.LoadedApk", wr.get(), "mClassLoader"));

RefInvoke.setFieldOjbect("android.app.LoadedApk", "mClassLoader",

wr.get(), dLoader);

} catch (Exception e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

}

public void onCreate() {

{

// 如果源应用配置有Appliction对象，则替换为源应用Applicaiton，以便不影响源程序逻辑。

String appClassName = null;

try {

ApplicationInfo ai = this.getPackageManager()

.getApplicationInfo(this.getPackageName(),

PackageManager.GET_META_DATA);

Bundle bundle = ai.metaData;

if (bundle != null

&& bundle.containsKey("APPLICATION_CLASS_NAME")) {

appClassName = bundle.getString("APPLICATION_CLASS_NAME");

} else {

return;

}

} catch (NameNotFoundException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

Object currentActivityThread = RefInvoke.invokeStaticMethod(

"android.app.ActivityThread", "currentActivityThread",

new Class[] {}, new Object[] {});

Object mBoundApplication = RefInvoke.getFieldOjbect(

"android.app.ActivityThread", currentActivityThread,

"mBoundApplication");

Object loadedApkInfo = RefInvoke.getFieldOjbect(

"android.app.ActivityThread$AppBindData",

mBoundApplication, "info");

RefInvoke.setFieldOjbect("android.app.LoadedApk", "mApplication",

loadedApkInfo, null);

Object oldApplication = RefInvoke.getFieldOjbect(

"android.app.ActivityThread", currentActivityThread,

"mInitialApplication");

ArrayList<Application> mAllApplications = (ArrayList<Application>) RefInvoke

.getFieldOjbect("android.app.ActivityThread",

currentActivityThread, "mAllApplications");

mAllApplications.remove(oldApplication);

ApplicationInfo appinfo_In_LoadedApk = (ApplicationInfo) RefInvoke

.getFieldOjbect("android.app.LoadedApk", loadedApkInfo,

"mApplicationInfo");

ApplicationInfo appinfo_In_AppBindData = (ApplicationInfo) RefInvoke

.getFieldOjbect("android.app.ActivityThread$AppBindData",

mBoundApplication, "appInfo");

appinfo_In_LoadedApk.className = appClassName;

appinfo_In_AppBindData.className = appClassName;

Application app = (Application) RefInvoke.invokeMethod(

"android.app.LoadedApk", "makeApplication", loadedApkInfo,

new Class[] { boolean.class, Instrumentation.class },

new Object[] { false, null });

RefInvoke.setFieldOjbect("android.app.ActivityThread",

"mInitialApplication", currentActivityThread, app);

HashMap mProviderMap = (HashMap) RefInvoke.getFieldOjbect(

"android.app.ActivityThread", currentActivityThread,

"mProviderMap");

Iterator it = mProviderMap.values().iterator();

while (it.hasNext()) {

Object providerClientRecord = it.next();

Object localProvider = RefInvoke.getFieldOjbect(

"android.app.ActivityThread$ProviderClientRecord",

providerClientRecord, "mLocalProvider");

RefInvoke.setFieldOjbect("android.content.ContentProvider",

"mContext", localProvider, app);

}

app.onCreate();

}

}

private void splitPayLoadFromDex(byte[] data) throws IOException {

byte[] apkdata = decrypt(data);

int ablen = apkdata.length;

byte[] dexlen = new byte[4];

System.arraycopy(apkdata, ablen - 4, dexlen, 0, 4);

ByteArrayInputStream bais = new ByteArrayInputStream(dexlen);

DataInputStream in = new DataInputStream(bais);

int readInt = in.readInt();

System.out.println(Integer.toHexString(readInt));

byte[] newdex = new byte[readInt];

System.arraycopy(apkdata, ablen - 4 - readInt, newdex, 0, readInt);

File file = new File(apkFileName);

try {

FileOutputStream localFileOutputStream = new FileOutputStream(file);

localFileOutputStream.write(newdex);

localFileOutputStream.close();

} catch (IOException localIOException) {

throw new RuntimeException(localIOException);

}

ZipInputStream localZipInputStream = new ZipInputStream(

new BufferedInputStream(new FileInputStream(file)));

while (true) {

ZipEntry localZipEntry = localZipInputStream.getNextEntry();

if (localZipEntry == null) {

localZipInputStream.close();

break;

}

String name = localZipEntry.getName();

if (name.startsWith("lib/") && name.endsWith(".so")) {

File storeFile = new File(libPath + "/"

+ name.substring(name.lastIndexOf('/')));

storeFile.createNewFile();

FileOutputStream fos = new FileOutputStream(storeFile);

byte[] arrayOfByte = new byte[1024];

while (true) {

int i = localZipInputStream.read(arrayOfByte);

if (i == -1)

break;

fos.write(arrayOfByte, 0, i);

}

fos.flush();

fos.close();

}

localZipInputStream.closeEntry();

}

localZipInputStream.close();

}

private byte[] readDexFileFromApk() throws IOException {

ByteArrayOutputStream dexByteArrayOutputStream = new ByteArrayOutputStream();

ZipInputStream localZipInputStream = new ZipInputStream(

new BufferedInputStream(new FileInputStream(

this.getApplicationInfo().sourceDir)));

while (true) {

ZipEntry localZipEntry = localZipInputStream.getNextEntry();

if (localZipEntry == null) {

localZipInputStream.close();

break;

}

if (localZipEntry.getName().equals("classes.dex")) {

byte[] arrayOfByte = new byte[1024];

while (true) {

int i = localZipInputStream.read(arrayOfByte);

if (i == -1)

break;

dexByteArrayOutputStream.write(arrayOfByte, 0, i);

}

}

localZipInputStream.closeEntry();

}

localZipInputStream.close();

return dexByteArrayOutputStream.toByteArray();

}

// //直接返回数据，读者可以添加自己解密方法

private byte[] decrypt(byte[] data) {

return data;

}

[java] view plain copy

package com.android.dexunshell;

import java.io.BufferedInputStream;

import java.io.ByteArrayInputStream;

import java.io.ByteArrayOutputStream;

import java.io.DataInputStream;

import java.io.File;

import java.io.FileInputStream;

import java.io.FileOutputStream;

import java.io.IOException;

import java.lang.ref.WeakReference;

import java.util.ArrayList;

import java.util.HashMap;

import java.util.Iterator;

import java.util.zip.ZipEntry;

import java.util.zip.ZipInputStream;

import dalvik.system.DexClassLoader;

import android.app.Application;

import android.content.pm.ApplicationInfo;

import android.content.pm.PackageManager;

import android.content.pm.PackageManager.NameNotFoundException;

import android.os.Bundle;

public class ProxyApplication extends Application {

private static final String appkey = "APPLICATION_CLASS_NAME";

private String apkFileName;

private String odexPath;

private String libPath;

protected void attachBaseContext(Context base) {

super.attachBaseContext(base);

try {

File odex = this.getDir("payload_odex", MODE_PRIVATE);

File libs = this.getDir("payload_lib", MODE_PRIVATE);

odexPath = odex.getAbsolutePath();

libPath = libs.getAbsolutePath();

apkFileName = odex.getAbsolutePath() + "/payload.apk";

File dexFile = new File(apkFileName);

if (!dexFile.exists())

dexFile.createNewFile();

// 读取程序classes.dex文件

byte[] dexdata = this.readDexFileFromApk();

// 分离出解壳后的apk文件已用于动态加载

this.splitPayLoadFromDex(dexdata);

// 配置动态加载环境

Object currentActivityThread = RefInvoke.invokeStaticMethod(

"android.app.ActivityThread", "currentActivityThread",

new Class[] {}, new Object[] {});

String packageName = this.getPackageName();

HashMap mPackages = (HashMap) RefInvoke.getFieldOjbect(

"android.app.ActivityThread", currentActivityThread,

"mPackages");

WeakReference wr = (WeakReference) mPackages.get(packageName);

DexClassLoader dLoader = new DexClassLoader(apkFileName, odexPath,

libPath, (ClassLoader) RefInvoke.getFieldOjbect(

"android.app.LoadedApk", wr.get(), "mClassLoader"));

RefInvoke.setFieldOjbect("android.app.LoadedApk", "mClassLoader",

wr.get(), dLoader);

} catch (Exception e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

}

public void onCreate() {

{

// 如果源应用配置有Appliction对象，则替换为源应用Applicaiton，以便不影响源程序逻辑。

String appClassName = null;

try {

ApplicationInfo ai = this.getPackageManager()

.getApplicationInfo(this.getPackageName(),

PackageManager.GET_META_DATA);

Bundle bundle = ai.metaData;

if (bundle != null

&& bundle.containsKey("APPLICATION_CLASS_NAME")) {

appClassName = bundle.getString("APPLICATION_CLASS_NAME");

} else {

return;

}

} catch (NameNotFoundException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

Object currentActivityThread = RefInvoke.invokeStaticMethod(

"android.app.ActivityThread", "currentActivityThread",

new Class[] {}, new Object[] {});

Object mBoundApplication = RefInvoke.getFieldOjbect(

"android.app.ActivityThread", currentActivityThread,

"mBoundApplication");

Object loadedApkInfo = RefInvoke.getFieldOjbect(

"android.app.ActivityThread$AppBindData",

mBoundApplication, "info");

RefInvoke.setFieldOjbect("android.app.LoadedApk", "mApplication",

loadedApkInfo, null);

Object oldApplication = RefInvoke.getFieldOjbect(

"android.app.ActivityThread", currentActivityThread,

"mInitialApplication");

ArrayList<Application> mAllApplications = (ArrayList<Application>) RefInvoke

.getFieldOjbect("android.app.ActivityThread",

currentActivityThread, "mAllApplications");

mAllApplications.remove(oldApplication);

ApplicationInfo appinfo_In_LoadedApk = (ApplicationInfo) RefInvoke

.getFieldOjbect("android.app.LoadedApk", loadedApkInfo,

"mApplicationInfo");

ApplicationInfo appinfo_In_AppBindData = (ApplicationInfo) RefInvoke

.getFieldOjbect("android.app.ActivityThread$AppBindData",

mBoundApplication, "appInfo");

appinfo_In_LoadedApk.className = appClassName;

appinfo_In_AppBindData.className = appClassName;

Application app = (Application) RefInvoke.invokeMethod(

"android.app.LoadedApk", "makeApplication", loadedApkInfo,

new Class[] { boolean.class, Instrumentation.class },

new Object[] { false, null });

RefInvoke.setFieldOjbect("android.app.ActivityThread",

"mInitialApplication", currentActivityThread, app);

HashMap mProviderMap = (HashMap) RefInvoke.getFieldOjbect(

"android.app.ActivityThread", currentActivityThread,

"mProviderMap");

Iterator it = mProviderMap.values().iterator();

while (it.hasNext()) {

Object providerClientRecord = it.next();

Object localProvider = RefInvoke.getFieldOjbect(

"android.app.ActivityThread$ProviderClientRecord",

providerClientRecord, "mLocalProvider");

RefInvoke.setFieldOjbect("android.content.ContentProvider",

"mContext", localProvider, app);

}

app.onCreate();

}

}

private void splitPayLoadFromDex(byte[] data) throws IOException {

byte[] apkdata = decrypt(data);

int ablen = apkdata.length;

byte[] dexlen = new byte[4];

System.arraycopy(apkdata, ablen - 4, dexlen, 0, 4);

ByteArrayInputStream bais = new ByteArrayInputStream(dexlen);

DataInputStream in = new DataInputStream(bais);

int readInt = in.readInt();

System.out.println(Integer.toHexString(readInt));

byte[] newdex = new byte[readInt];

System.arraycopy(apkdata, ablen - 4 - readInt, newdex, 0, readInt);

File file = new File(apkFileName);

try {

FileOutputStream localFileOutputStream = new FileOutputStream(file);

localFileOutputStream.write(newdex);

localFileOutputStream.close();

} catch (IOException localIOException) {

throw new RuntimeException(localIOException);

}

ZipInputStream localZipInputStream = new ZipInputStream(

new BufferedInputStream(new FileInputStream(file)));

while (true) {

ZipEntry localZipEntry = localZipInputStream.getNextEntry();

if (localZipEntry == null) {

localZipInputStream.close();

break;

}

String name = localZipEntry.getName();

if (name.startsWith("lib/") && name.endsWith(".so")) {

File storeFile = new File(libPath + "/"

+ name.substring(name.lastIndexOf('/')));

storeFile.createNewFile();

FileOutputStream fos = new FileOutputStream(storeFile);

byte[] arrayOfByte = new byte[1024];

while (true) {

int i = localZipInputStream.read(arrayOfByte);

if (i == -1)

break;

fos.write(arrayOfByte, 0, i);

}

fos.flush();

fos.close();

}

localZipInputStream.closeEntry();

}

localZipInputStream.close();

}

private byte[] readDexFileFromApk() throws IOException {

ByteArrayOutputStream dexByteArrayOutputStream = new ByteArrayOutputStream();

ZipInputStream localZipInputStream = new ZipInputStream(

new BufferedInputStream(new FileInputStream(

this.getApplicationInfo().sourceDir)));

while (true) {

ZipEntry localZipEntry = localZipInputStream.getNextEntry();

if (localZipEntry == null) {

localZipInputStream.close();

break;

}

if (localZipEntry.getName().equals("classes.dex")) {

byte[] arrayOfByte = new byte[1024];

while (true) {

int i = localZipInputStream.read(arrayOfByte);

if (i == -1)

break;

dexByteArrayOutputStream.write(arrayOfByte, 0, i);

}

}

localZipInputStream.closeEntry();

}

localZipInputStream.close();

return dexByteArrayOutputStream.toByteArray();

}

// //直接返回数据，读者可以添加自己解密方法

private byte[] decrypt(byte[] data) {

return data;

}

}

RefInvoke为反射调用工具类：

[java] view plain copy

package com.android.dexunshell;

import java.lang.reflect.Field;

import java.lang.reflect.InvocationTargetException;

import java.lang.reflect.Method;

public class RefInvoke {

public static Object invokeStaticMethod(String class_name, String method_name, Class[] pareTyple, Object[] pareVaules){

try {

Class obj_class = Class.forName(class_name);

Method method = obj_class.getMethod(method_name,pareTyple);

return method.invoke(null, pareVaules);

} catch (SecurityException e) {

// TODO Auto-generated catch block

e.printStackTrace();

} catch (IllegalArgumentException e) {

// TODO Auto-generated catch block

e.printStackTrace();

} catch (IllegalAccessException e) {

// TODO Auto-generated catch block

e.printStackTrace();

} catch (NoSuchMethodException e) {

// TODO Auto-generated catch block

e.printStackTrace();

} catch (InvocationTargetException e) {

// TODO Auto-generated catch block

e.printStackTrace();

} catch (ClassNotFoundException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

return null;

}

public static Object invokeMethod(String class_name, String method_name, Object obj ,Class[] pareTyple, Object[] pareVaules){

try {

Class obj_class = Class.forName(class_name);

Method method = obj_class.getMethod(method_name,pareTyple);

return method.invoke(obj, pareVaules);

} catch (SecurityException e) {

// TODO Auto-generated catch block

e.printStackTrace();

} catch (IllegalArgumentException e) {

// TODO Auto-generated catch block

e.printStackTrace();

} catch (IllegalAccessException e) {

// TODO Auto-generated catch block

e.printStackTrace();

} catch (NoSuchMethodException e) {

// TODO Auto-generated catch block

e.printStackTrace();

} catch (InvocationTargetException e) {

// TODO Auto-generated catch block

e.printStackTrace();

} catch (ClassNotFoundException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

return null;

}

public static Object getFieldOjbect(String class_name,Object obj, String filedName){

try {

Class obj_class = Class.forName(class_name);

Field field = obj_class.getDeclaredField(filedName);

field.setAccessible(true);

return field.get(obj);

} catch (SecurityException e) {

// TODO Auto-generated catch block

e.printStackTrace();

} catch (NoSuchFieldException e) {

// TODO Auto-generated catch block

e.printStackTrace();

} catch (IllegalArgumentException e) {

// TODO Auto-generated catch block

e.printStackTrace();

} catch (IllegalAccessException e) {

// TODO Auto-generated catch block

e.printStackTrace();

} catch (ClassNotFoundException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

return null;

}

public static Object getStaticFieldOjbect(String class_name, String filedName){

try {

Class obj_class = Class.forName(class_name);

Field field = obj_class.getDeclaredField(filedName);

field.setAccessible(true);

return field.get(null);

} catch (SecurityException e) {

// TODO Auto-generated catch block

e.printStackTrace();

} catch (NoSuchFieldException e) {

// TODO Auto-generated catch block

e.printStackTrace();

} catch (IllegalArgumentException e) {

// TODO Auto-generated catch block

e.printStackTrace();

} catch (IllegalAccessException e) {

// TODO Auto-generated catch block

e.printStackTrace();

} catch (ClassNotFoundException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

return null;

}

public static void setFieldOjbect(String classname, String filedName, Object obj, Object filedVaule){

try {

Class obj_class = Class.forName(classname);

Field field = obj_class.getDeclaredField(filedName);

field.setAccessible(true);

field.set(obj, filedVaule);

} catch (SecurityException e) {

// TODO Auto-generated catch block

e.printStackTrace();

} catch (NoSuchFieldException e) {

// TODO Auto-generated catch block

e.printStackTrace();

} catch (IllegalArgumentException e) {

// TODO Auto-generated catch block

e.printStackTrace();

} catch (IllegalAccessException e) {

// TODO Auto-generated catch block

e.printStackTrace();

} catch (ClassNotFoundException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

}

public static void setStaticOjbect(String class_name, String filedName, Object filedVaule){

try {

Class obj_class = Class.forName(class_name);

Field field = obj_class.getDeclaredField(filedName);

field.setAccessible(true);

field.set(null, filedVaule);

} catch (SecurityException e) {

// TODO Auto-generated catch block

e.printStackTrace();

} catch (NoSuchFieldException e) {

// TODO Auto-generated catch block

e.printStackTrace();

} catch (IllegalArgumentException e) {

// TODO Auto-generated catch block

e.printStackTrace();

} catch (IllegalAccessException e) {

// TODO Auto-generated catch block

e.printStackTrace();

} catch (ClassNotFoundException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

}

}

三、总结

本文代码基本实现了APK文件的加壳及脱壳原理，该代码作为实验代码还有诸多地方需要改进。比如：

1、加壳数据的加密算法的添加。

2、脱壳代码由java语言实现，可通过C代码的实现对脱壳逻辑进行保护，以达到更好的反逆向分析效果。