Android Debug Bridge version 1.0.29

 -d - directs command to the only connected USB device
  returns an error if more than one USB device is![image](img/backarrow.jpg)
 present.
 -e - directs command to the only running emulator.
  returns an error if more than one emulator is running.
 -s  <  serial number> - directs command to the USB device or emulator with
  the given serial number. Overrides ANDROID_SERIAL
  environment variable.
 -p  <  product name or path> - simple product name like 'sooner', or
  a relative/absolute path to a product
  out directory like 'out/target/product/sooner'.
  If -p is not specified, the ANDROID_PRODUCT_OUT
  environment variable is used, which must
  be an absolute path.
 devices    - list all connected devices
 connect  <  host  >  [:<port>]    - connect to a device via TCP/IP
  Port 5555 is used by default if no port number is![image](img/backarrow.jpg)
 specified.
 disconnect [<host  >  [:<port>]] - disconnect from a TCP/IP device.
  Port 5555 is used by default if no port number is![image](img/backarrow.jpg)
 specified.
  Using this command with no additional arguments
  will disconnect from all connected TCP/IP devices.

device commands:
  adb push  <  local  >  <remote>    -      copy file/dir to device
  adb pull  <  remote  >  [<local>]    -      copy file/dir from device
  adb sync [ <directory> ]    - copy host-  >  device only if changed
  (−l means list but don't copy)
  (see 'adb help all')
  adb shell    - run remote shell interactively
  adb shell  <  command> - run remote shell command
  adb emu  <  command> - run emulator console command
  adb logcat [ <filter-spec> ]    - View device log
  adb forward  <  local  >  <remote  >   − forward socket connections
     forward specs are one of:
  tcp:<port>
  localabstract:<unix domain socket name>
  localreserved:<unix domain socket name>
  localfilesystem:<unix domain socket name>
  dev:<character device name>
  jdwp:<process pid  >  (remote only)
  adb jdwp    - list PIDs of processes hosting a JDWP transport
  adb install [−l] [−r] [−s]  <  file  >  − push this package file to the device and install![image](img/backarrow.jpg)
 it
  ('-l' means forward-lock the app)
  ('-r' means reinstall the app, keeping its data)
  ('-s' means install on SD card instead of internal![image](img/backarrow.jpg)
 storage)
  adb uninstall [−k]  <  package  >  − remove this app package from the device
  ('-k' means keep the data and cache directories)
  adb bugreport    -     return all information from the device
  that should be included in a bug report.

  adb backup [−f  <  file>] [−apk|-noapk] [−shared|-noshared] [−all] [−system|-nosystem]![image](img/backarrow.jpg)
 [<packages...>]
     -     write an archive of the device's data to  <  file  >  .
  If no -f option is supplied then the data is written
  to "backup.ab" in the current directory.
  (−apk|-noapk enable/disable backup of the .apks![image](img/backarrow.jpg)
 themselves
  in the archive; the default is noapk.)
  (−shared|-noshared enable/disable backup of the![image](img/backarrow.jpg)
 device's
  shared storage / SD card contents; the default is![image](img/backarrow.jpg)
 noshared.)
  (−all means to back up all installed applications)
  (−system|-nosystem toggles whether -all automatically![image](img/backarrow.jpg)
 includes
  system applications; the default is to include![image](img/backarrow.jpg)
 system apps)
  (<packages...  >  is the list of applications to be![image](img/backarrow.jpg)
 backed up. If
  the -all or -shared flags are passed, then the![image](img/backarrow.jpg)
 package
  list is optional. Applications explicitly given![image](img/backarrow.jpg)
 on the
  command line will be included even if –nosystem![image](img/backarrow.jpg)
 would
  ordinarily cause them to be omitted.)

  adb restore  <  file> - restore device contents from the  <  file  >  backup archive

  adb help    -     show this help message
  adb version    -     show version num

scripting:
  adb wait-for-device    -     block until device is online
  adb start-server    -     ensure that there is a server running
  adb kill-server    -     kill the server if it is running
  adb get-state    -     prints: offline | bootloader | device
  adb get-serialno    -     prints: <serial-number>
  adb status-window    -     continuously print device status for a specified device
  adb remount    -     remounts the /system partition on the device read-write
  adb reboot [bootloader|recovery] - reboots the device, optionally into the![image](img/backarrow.jpg)
 bootloader or recovery program
  adb reboot-bootloader    -     reboots the device into the bootloader
  adb root    -     restarts the adbd daemon with root permissions
  adb usb    -     restarts the adbd daemon listening on USB
  adb tcpip  <  port> -     restarts the adbd daemon listening on TCP on the![image](img/backarrow.jpg)
 specified port
networking:
  adb ppp  <  tty  >  [parameters]    -     Run PPP over USB.
 Note: you should not automatically start a PPP connection.
 <tty  >  refers to the tty for PPP stream. Eg. dev:/dev/omap_csmi_tty1
 [parameters] - Eg. defaultroute debug dump local notty usepeerdns

adb sync notes: adb sync [ <directory> ]
  <localdir  >  can be interpreted in several ways:

  - If  <  directory  >  is not specified, both /system and /data partitions will be updated.

  - If it is "system" or "data", only the corresponding partition
  is updated.

environmental variables:
  ADB_TRACE - Print debug information. A comma separated list of![image](img/backarrow.jpg)
 the following values
  1 or all, adb, sockets, packets, rwx, usb, sync,![image](img/backarrow.jpg)
 sysdeps, transport, jdwp
  ANDROID_SERIAL - The serial number to connect to. -s takes priority![image](img/backarrow.jpg)
 over this if given.
  ANDROID_LOG_TAGS - When used with the logcat option, only these debug![image](img/backarrow.jpg)
 tags are printed.

$ ./adb shell
# cd /data/app
# ls
net.zenconsult.android.chucknorris-1.apk
test_limits_host
ApiDemos.apk
test_list_host
test_set_host
CubeLiveWallpapers.apk
test_iostream_host
test_iomanip_host
SoftKeyboard.apk
test_iterator_host
test_vector_host
test_algorithm_host
test_uninitialized_host
GestureBuilder.apk
test_sstream_host
test_char_traits_host
test_memory_host
test_ios_base_host
test_type_traits_host
test_ios_pos_types_host
test_streambuf_host
test_functional_host
test_string_host

adb pull /data/app/ net.zenconsult.android.chucknorris-1.apk.

$ unzip net.zenconsult.android.chucknorris-1.apk
Archive: net.zenconsult.android.chucknorris-1.apk
  inflating: res/layout/main.xml
  inflating: AndroidManifest.xml
 extracting: resources.arsc
 extracting: res/drawable-hdpi/ic_launcher.png
 extracting: res/drawable-ldpi/ic_launcher.png
 extracting: res/drawable-mdpi/ic_launcher.png
  inflating: classes.dex
  inflating: META-INF/MANIFEST.MF
  inflating: META-INF/CERT.SF
  inflating: META-INF/CERT.RSA
$

$ dexdump –d classes.dex
...
...
Virtual methods -
  #0 : (in Lnet/zenconsult/android/chucknorris/e;)
  name : 'a'
  type : '()Ljava/lang/String;'
  access : 0x0011 (PUBLIC FINAL)
  code -
  registers : 16
  ins : 1
  outs : 2
  insns size : 180 16-bit code units
0009d4: |[0009d4] net.zenconsult.android![image](img/backarrow.jpg)
.chucknorris.e.a:()Ljava/lang/String;
0009e4: 1202 |0000: const/4 v2, #int 0 // #0
0009e6: 1a00 5100 |0001: const-string v0,![image](img/backarrow.jpg)
 "[http://www.chucknorrisfacts.com/](http://www.chucknorrisfacts.com/)" // string@0051
0009ea: 7020 2900 0f00 |0003: invoke-direct {v15, v0},![image](img/backarrow.jpg)
 Lnet/zenconsult/android/chucknorris/e;.a:(Ljava/lang/String;)Ljava/io/InputStream;![image](img/backarrow.jpg)
 // method@0029
0009f0: 0c05 |0006: move-result-object v5
0009f2: 7100 1600 0000 |0007: invoke-static {},![image](img/backarrow.jpg)
 Ljavax/xml/parsers/DocumentBuilderFactory;.newInstance:()Ljavax/xml/![image](img/backarrow.jpg)
parsers/DocumentBuilderFactory; // method@0016
0009f8: 0c00 |000a: move-result-object v0
0009fa: 1a01 0000 |000b: const-string v1, "" // string@0000
0009fe: 2206 1100 |000d: new-instance v6,![image](img/backarrow.jpg)
 Ljava/util/Vector; // type@0011
000a02: 7010 1000 0600 |000f: invoke-direct {v6},![image](img/backarrow.jpg)
 Ljava/util/Vector;.  <  init>:()V // method@0010
000a08: 6e10 1500 0000 |0012: invoke-virtual {v0},![image](img/backarrow.jpg)
 Ljavax/xml/parsers/DocumentBuilderFactory;.newDocumentBuilder:()Ljavax/xml![image](img/backarrow.jpg)
/parsers/DocumentBuilder; // method@0015
000a0e: 0c00 |0015: move-result-object v0
000a10: 6e20 1400 5000 |0016: invoke-virtual {v0, v5},
...
...

$ java -jar ∼/Downloads/baksmali-1.2.8.jar classes.dex
$ cd out/net/zenconsult/android/chucknorris/
$ ls
ChuckNorrisFactsActivity.smali b.smali d.smali
a.smali c.smali e.smali
$

.class public final Lnet/zenconsult/android/chucknorris/b;
.super Ljava/lang/Thread;

# instance fields
.field private a:Lnet/zenconsult/android/chucknorris/a;

# direct methods
.method public constructor  <  init  >  (Lnet/zenconsult/android/chucknorris/a;)V
  .registers 2

  invoke-direct {p0}, Ljava/lang/Thread;-  >  <init  >  ()V

  iput-object p1, p0, Lnet/zenconsult/android/chucknorris/b;-  >  a:Lnet/zenconsult![image](img/backarrow.jpg)
/android/chucknorris/a;

  return-void
.end method

# virtual methods
.method public final run()V
  .registers 3

  new-instance v0, Lnet/zenconsult/android/chucknorris/e;

  invoke-direct {v0}, Lnet/zenconsult/android/chucknorris/e;-  >  <init  >  ()V

  iget-object v1, p0, Lnet/zenconsult/android/chucknorris/b;-  >  a:Lnet/zenconsult![image](img/backarrow.jpg)
/android/chucknorris/a;

  invoke-virtual {v0}, Lnet/zenconsult/android/chucknorris/e;-  >  a()Ljava/lang/String;

  move-result-object v0

  invoke-interface {v1, v0}, Lnet/zenconsult/android/chucknorris/a;-  >  a![image](img/backarrow.jpg)
(Ljava/lang/String;)V

  return-void
.end method

package net.zenconsult.android.chucknorris;

**import** android.app.Activity;
**import** android.os.Bundle;
**import** android.view.View;
**import** android.widget.Button;
**import** android.widget.TextView;

**public class** ChuckNorrisFactsActivity **extends** Activity **implements** CommsEvent {
        **private** Activity activity;
        **private** TextView view;
        **private** CommsEvent event;

        /** Called when the activity is first created. */
        @Override
        **public void** onCreate(Bundle savedInstanceState) {
                **super**.onCreate(savedInstanceState);
                setContentView(R.layout. *main* );
                activity = **this**;
                event = **this**;
                view = (TextView) findViewById(R.id.*editText1*);

                // Click Button
                **final** Button button = (Button) findViewById(R.id.*button1*);
                button.setOnClickListener(**new** View.OnClickListener() {
                        **public void** onClick(View v) {
                                view.setText("Fetching fact...");
                                CommsNotifier c = **new** CommsNotifier(event);
                                c.start();
                        }
                });
        }

        @Override
        **public void** onTextReceived(**final** String text) {
                runOnUiThread(**new** Runnable() {
                        **public void** run() {
                                view.setText(text);
                        }
                });

        }
}

**package** net.zenconsult.android.chucknorris;

**public interface** CommsEvent {
        **public void** onTextReceived(String text);
}

**package** net.zenconsult.android.chucknorris;

**public class** CommsNotifier **extends** Thread {
        **private** CommsEvent event;

        **public** CommsNotifier(CommsEvent evt) {
        event = evt;
        }

        **public void** run() {
        Comms c = **new** Comms();
        event.onTextReceived(c.get());
        }
}

**package** net.zenconsult.android.chucknorris;

**import** java.io.IOException;
**import** java.io.InputStream;
**import** java.util.Random;
**import** java.util.Vector;

**import** javax.xml.parsers.DocumentBuilder;
**import** javax.xml.parsers.DocumentBuilderFactory;
**import** javax.xml.parsers.ParserConfigurationException;

**import** org.apache.http.HttpResponse;
**import** org.apache.http.client.ClientProtocolException;
**import** org.apache.http.client.methods.HttpGet;
**import** org.apache.http.impl.client.DefaultHttpClient;
**import** org.apache.http.util.EntityUtils;
**import** org.w3c.dom.Document;
**import** org.w3c.dom.NamedNodeMap;
**import** org.w3c.dom.Node;
**import** org.w3c.dom.NodeList;
**import** org.xml.sax.SAXException;

**import** android.app.Activity;
**import** android.content.Context;
**import** android.util.Log;
**import** android.widget.Toast;

**public class** Comms {
        **private final** String url = "[http://www.chucknorrisfacts.com/](http://www.chucknorrisfacts.com/)";

        **private** DefaultHttpClient client;

        **public** Comms() {

        client = **new** DefaultHttpClient();
        }

        **public** String get() {
        InputStream pageStream = doGetAsInputStream(url);
        DocumentBuilderFactory dbFactory = DocumentBuilderFactory.*newInstance*();
        DocumentBuilder db = **null**;
        Document doc = **null;**
        String pageText = "";
        Vector        < String >        quotes = **new** Vector        < String >        ();
        **try** {
        db = dbFactory.newDocumentBuilder();
        doc = db.parse(pageStream);
        NodeList nl = doc.getElementsByTagName("div");
        **for** (**int** x = 0; x < nl.getLength(); ++x) {
        Node node = nl.item(x);
        NamedNodeMap attributes = node.getAttributes();
        **for** (**int** y = 0; y        <        attributes.getLength(); ++y) {
        **if** (attributes.getNamedItem("class") ! = null) {
        Node attribute =![image](img/backarrow.jpg)
       attributes.getNamedItem("class");
        **if** (attribute.getNodeValue()
        .equals("views-![image](img/backarrow.jpg)
field-title")) {
        NodeList children =![image](img/backarrow.jpg)
       node.getChildNodes();
        **for** (**int** z = 0; z <![image](img/backarrow.jpg)
       children.getLength(); ++z) {
        Node child =![image](img/backarrow.jpg)
       children.item(z);
        **if** (child.getNodeName()
        ![image](img/backarrow.jpg)
.equalsIgnoreCase("span"))
        quotes.add![image](img/backarrow.jpg)
(child.getTextContent());
        }
        }
        }

        }
        }
        Random r = **new** Random();
        pageText = quotes.get(r.nextInt(quotes.size() - 1));
        pageStream.close();
        } **catch** (SAXException e) {
              // **TODO** Auto-generated **catch** block
        e.printStackTrace();
        } **catch** (IOException e) {
              // **TODO** Auto-generated catch block
        e.printStackTrace();
        } **catch** (ParserConfigurationException e) {
              // **TODO** Auto-generated catch block
        e.printStackTrace();
        }
        **return** pageText;
        }

        **public** String doGetAsString(String url) {
        HttpGet request = **new** HttpGet(url);
        String result = "";
        **try** {
        HttpResponse response = client.execute(request);
        **int** code = response.getStatusLine().getStatusCode();
        **if** (code == 200) {
        result = EntityUtils.*toString*(response.getEntity());
        } **else** {
        Log.*e*("CN", "Non 200 Status Code "        +        code);
        }
        } **catch** (ClientProtocolException e) {
              // **TODO** Auto-generated catch block
        e.printStackTrace();
        } **catch** (IOException e) {
              // **TODO** Auto-generated catch block
        e.printStackTrace();
        }
        **return** result;

        }

        **public** InputStream doGetAsInputStream(String url) {
        HttpGet request = **new** HttpGet(url);
        InputStream result = **null**;
        **try** {
        HttpResponse response = client.execute(request);
        **int** code = response.getStatusLine().getStatusCode();
        **if** (code == 200) {
        result = response.getEntity().getContent();
        } **else** {
        Log.*e*("CN", "Non 200 Status Code "        +        code);
        }
        } **catch** (ClientProtocolException e) {
              // **TODO** Auto-generated catch block
        e.printStackTrace();
        } **catch** (IOException e) {
              // **TODO** Auto-generated catch block
        e.printStackTrace();
        }
        **return** result;
        }
}

**package** net.zenconsult.android.chucknorris;

**import** java.util.UUID;

**import** com.android.vending.licensing.AESObfuscator;
**import** com.android.vending.licensing.LicenseChecker;
**import** com.android.vending.licensing.LicenseCheckerCallback;
**import** com.android.vending.licensing.ServerManagedPolicy;

**import** android.app.Activity;
**import** android.content.Context;
**import** android.os.Build;
**import** android.os.Bundle;
**import** android.provider.Settings.Secure;
**import** android.view.View;
**import** android.view.Window;
**import** android.widget.Button;
**import** android.widget.TextView;
**import** android.widget.Toast;

**public class** ChuckNorrisFactsActivity **extends** Activity **implements** CommsEvent {
        **private** Button button;
        **private** TextView view;
        **private** Activity activity;
        **private** CommsEvent event;
        **private** LicCallBack lcb;
        **private static** final String*PUB_KEY* = "MIIBI...";// Add your Base64 Public
        // key here
        **private** staticfinal byte[]*SALT* = **new byte**[] { −118, -112, 38, 124, 15,
        -121, 59, 93, 35, -55, 14, -15, -52, 67, -53, 54, 111, -28,![image](img/backarrow.jpg)
       -87, 12 };

        /** Called when the activity is first created. */
        @Override
        public void onCreate(Bundle savedInstanceState) {
        **super**.onCreate(savedInstanceState);
        requestWindowFeature(Window.*FEATURE_INDETERMINATE_PROGRESS*);
        setContentView(R.layout.*main*);
        event = **this**;
        activity = **this**;
        view = (TextView) findViewById(R.id.*editText1*);

        // Click Button
        button = (Button) findViewById(R.id.*button1*);
        button.setOnClickListener(**new** View.OnClickListener() {
        public void onClick(View v) {
        // Do License Check before allowing click

        // Generate a Unique ID
        String deviceId = Secure.*getString*(getContentResolver(),
        Secure.*ANDROID_ID*);
        String serialId = Build.*SERIAL*;
        UUID uuid = **new** UUID(deviceId.hashCode(),![image](img/backarrow.jpg)
       serialId.hashCode());
        String identity = uuid.toString();
        Context ctx = activity.getApplicationContext();

        // Create an Obfuscatorand a Policy
        AESObfuscator obf = **new** AESObfuscator(*SALT*,![image](img/backarrow.jpg)
       get**Package**Name(),
        identity);
        ServerManagedPolicy policy = **new**![image](img/backarrow.jpg)
       ServerManagedPolicy(ctx, obf);

        // Create the LicenseChecker
        LicenseChecker lCheck = **new** LicenseChecker(ctx,![image](img/backarrow.jpg)
       policy,*PUB_KEY*);

        // Do the license check
        lcb = **new** LicCallBack();
        lCheck.checkAccess(lcb);
        }
        });
        }

        @Override
        public void onTextReceived(final String text) {
        runOnUiThread(**new** Runnable() {
        public void run() {
        setProgressBarIndeterminateVisibility(**false**);
        view.setText(text);
        button.setEnabled(**true**);

        }
        });

        }

        **public class** LicCallBack implements LicenseCheckerCallback {

        @Override
        public void allow() {
        if (isFinishing()) {
        return;
        }

        Toast toast = Toast.*makeText*(getApplicationContext(),![image](img/backarrow.jpg)
       "Licensed!",
        Toast.*LENGTH_LONG*);
        toast.show();
        button.setEnabled(**false**);
        setProgressBarIndeterminateVisibility(**true**);
        view.setText("Fetching fact...");
        CommsNotifier c = **new** CommsNotifier(event);
        c.start();
        }

        @Override
        public void dontAllow() {
        if (isFinishing()) {
        return;
        }
        Toast toast = Toast.*makeText*(getApplicationContext(),
        "Unlicensed!", Toast.*LENGTH_LONG*);
        toast.show();
        }

        @Override
        public void applicationError(ApplicationErrorCode errorCode) {
        // TODO Auto-generated method stub

        }

        }

}

AESObfuscator obf = new AESObfuscator(*SALT*, get**Package**Name(),identity);

public boolean allowAccess() {
        long ts = System.currentTimeMillis();
        if (mLastResponse == LicenseResponse.LICENSED) {
        // Check if the LICENSED response occurred within the validity timeout.
        if (ts        <        = mValidityTimestamp) {
        // Cached LICENSED response is still valid.
        return true;
        }
        } else if (mLastResponse == LicenseResponse.RETRY &&
        ts < mLastResponseTime        +        MILLIS_PER_MINUTE) {
        // Only allow access if we are within the retry period or we haven't![image](img/backarrow.jpg)
       used up our
        // max retries.
        return (ts        <        = mRetryUntil || mRetryCount        <        = mMaxRetries);
        }
        return false;
        }

**public void** processServerResponse(LicenseResponse response, ResponseData rawData) {

        // Update retry counter
        if (response != LicenseResponse.*RETRY*) {
        setRetryCount(0);
     } **else** {
        setRetryCount(mRetryCount        +        1);
     }

     **if** (response == LicenseResponse.*LICENSED*) {
        // Update server policy data
        Map        < String, String >        extras = decodeExtras(rawData.extra);
        mLastResponse = response;
        setValidityTimestamp(extras.get("VT"));
        setRetryUntil(extras.get("GT"));
        setMaxRetries(extras.get("GR"));
     } **else if** (response == LicenseResponse.*NOT_LICENSED*) {
        // Clear out stale policy data
        setValidityTimestamp(*DEFAULT_VALIDITY_TIMESTAMP*);
        setRetryUntil(*DEFAULT_RETRY_UNTIL*);
        setMaxRetries(*DEFAULT_MAX_RETRIES*);
     }

     setLastResponse(response);
     mPreferences.commit();
 }

```***  *****LVL 的有效使用**

如果您修改了 LVL 源代码(即您的策略)，使其成为您的应用独有的东西，那么这一努力是值得的。您可能犯的一个错误是使用 LVL 的普通实现，每个人都知道它的源代码。这使得有人更容易修补你的应用，绕过你的许可证检查程序。Justin Case 已经在 Android Police 网站上展示了这个漏洞。可以在[www . androidpolice . com/2010/08/23/exclusive-report-Google-Android-market-license-verification-easy-boxed-will-not-stop-pirates/](http://www.androidpolice.com/2010/08/23/exclusive-report-googles-android-market-license-verification-easily-circumvented-will-not-stop-pirates/)找到文章。诚然，这是一篇老文章，但它仍然展示了这样一个原则，即如果您知道源代码是什么样子，就可以很容易地理解和修改逆向工程代码。在这种情况下，Justin 在一个演示和一个实际的商业应用中演示了如何修补和绕过 LVL 检查。

Android 开发者博客的 Trevor Johns 为我们提供了另一套很好的指南。这篇文章非常值得一读，并列出了一些更有效地使用 LVL 的技巧。有一段代码非常有趣。看[图 9-22](#Fig000920) 。Trevor 告诉我们，攻击者可以猜测许可和未 _ 许可常量值的响应，然后交换它们，以便未经许可的用户可以完全使用该应用。为了防止这种情况，Trevor 向我们展示了一些代码，这些代码将对响应运行 CRC32 检查；不检查常量，而是检查常量的 CRC32 检查结果。我想在这个问题上多谈一点。想象一下，如果您不运行固定值的检查，而是执行另一个 HTTP fetch 来从您自己的服务器检索响应。

![9781430240624_Fig09-22.jpg](img/9781430240624_Fig09-22.jpg)

图 9-22 。备用响应验证思路

考虑清单 9-11 中的代码。您向服务器发出一个额外的请求，并从那里检索响应代码，而不是直接与一个数字进行比较。这样做的一个好处是，你可以以任何你喜欢的方式设计你的 ServerVerifier 对象。您甚至可以设置它，使响应代码每次都发生变化。您甚至可以考虑在代码中使用质询响应来改变每次的响应。

***[清单 9-11](#_list11) 。*** *修改验证功能*

```java
public void verify(PublicKey publicKey, int responseCode, String signedData, String![image](img/backarrow.jpg)
       signature) {
        // ... Response validation code omitted for brevity ...

        // Compute a derivative version of the response code
        // Rather than comparing to a static value, why not retrieve the value from![image](img/backarrow.jpg)
       a server that you control?

        java.util.zip.CRC32 crc32 = new java.util.zip.CRC32();
        crc32.update(responseCode);
        int transformedResponseCode = crc32.getValue();

        ServerVerifier sv = new ServerVerifier(); // This class will make an![image](img/backarrow.jpg)
       HTTP request to your server to fetch the code.
        int serverResponse = sv.retrieveLicensedCode(); // There is no limit![image](img/backarrow.jpg)
       to how you can create this routine.

        // ... put unrelated application code here ...
        // crc32(LICENSED) == 3523407757 But this part is calculated on your server.
        if (transformedResponse == serverResponse) {
        LicenseResponse limiterResponse = mDeviceLimiter.isDeviceAllowed(userId);
        handleResponse(limiterResponse, data);
        }

        ...
        ...
        ...

**if** (response == LicenseResponse.*LICENSED*)

ServerVerifier sv = new ServerVerifier();
**if** (response == sv.getLicensedResponse())
```***  *****混淆视听**

混淆 是你需要考虑的另一个要点。它适用于软件盗版，以及知识产权盗窃。模糊处理是将源代码中的所有类名、变量名和方法名更改为随机的、不相关的名称的过程。你可能想知道为什么我的反编译应用在目录列表中有像 a.smali 、 b.smali 、 c.smali 等文件。当我使用 BakSmali 反编译我的应用时，我是在二进制文件的模糊版本上运行它的。代码混淆器确保将我的类名(如 Comms 、 CommsEvent 、 CommsNotifier 等)更改为不主动提供它们所做工作的信息的类名。此外，如果您查看这些文件，您会发现方法名和成员名都被混淆了。这对于试图对代码进行逆向工程的人来说是非常令人沮丧的，并且它可以作为对知识产权或代码盗窃的极好的威慑。

模糊处理不能保证你的代码不会被窃取或盗版。它只是让逆向工程的任务变得更加困难。Android SDK 附带了一个名为 ProGuard 的混淆器。您可以使用 ProGuard 来混淆您的任何 Java 代码。你可以在[http://proguard.sourceforge.net/;](http://proguard.sourceforge.net/;)下载它，它是免费的开源软件。Android 开发者文档强烈建议你在打包应用发布时对代码进行模糊处理。如果您使用 Eclipse，那么这是一项简单的任务。在您的项目中找到您的 project.properties 文件(参见[图 9-23](#Fig000923) )并添加这一行(参见[图 9-24](#Fig000924) ):

```java
proguard.config = proguard.cfg