am 35b08bac: am edcf7c51: Merge "docs: Simplify and update the Signing page. Bug: 16296405" into klp-modular-docs

* commit '35b08bacc4e4ab937a5179b5b991f6509127f517':
  docs: Simplify and update the Signing page. Bug: 16296405

1 files changed, 243 insertions, 550 deletions

diff --git a/docs/html/tools/publishing/app-signing.jd b/docs/html/tools/publishing/app-signing.jd
index 1de1fd7..53e6e65 100644
--- a/docs/html/tools/publishing/app-signing.jd
+++ b/docs/html/tools/publishing/app-signing.jd
@@ -4,33 +4,26 @@ page.title=Signing Your Applications
 <div id="qv-wrapper">
 <div id="qv">
 
-<h2>Quickview</h2>
-
-<ul>
-<li>All Android apps <em>must</em> be signed</li>
-<li>You can sign with a self-signed key</li>
-<li>How you sign your apps is critical &mdash; read this document carefully</li>
-<li>Determine your signing strategy early in the development process</li>
-</ul>
-
 <h2>In this document</h2>
 
 <ol>
-<li><a href="#signing">Signing Process</a></li>
-<li><a href="#strategies">Signing Strategies</a></li>
-<li><a href="#setup">Basic Setup for Signing</a></li>
-<li><a href="#debugmode">Signing in Debug Mode</a></li>
-<li><a href="#releasemode">Signing Release Mode</a>
-    <ol>
-    <li><a href="#cert">Obtain a suitable private key</a></li>
-    <li><a href="#releasecompile">Compile the application in release mode</a></li>
-    <li><a href="#signapp">Sign your application with your private key</a></li>
-    <li><a href="#align">Align the final APK package</a></li>
-    <li><a href="#ExportWizard">Compile and sign with Eclipse ADT</a></li>
-    </ol>
+<li><a href="#overview">Signing Overview</a>
+  <ol>
+  	<li><a href="#debug-mode">Signing in Debug Mode</a></li>
+  	<li><a href="#release-mode">Signing in Release Mode</a></li>
+  	<li><a href="#wear-apps">Signing Android Wear Apps</a></li>
+  </ol>
 </li>
+<li><a href="#studio">Signing Your App in Android Studio</a>
+  <ol>
+  	<li><a href="sign-auto">Automatically Signing Your App</a></li>
+  </ol>
+</li>
+<li><a href="#adt">Signing Your App with the ADT plugin for Eclipse</a></li>
+<li><a href="#considerations">Signing Considerations</a></li>
 <li><a href="#secure-key">Securing Your Private Key</a></li>
-
+<li><a href="#expdebug">Expiry of the Debug Certificate</a></li>
+<li><a href="#signing-manually">Signing Your App Manually</a></li>
 </ol>
 
 <h2>See also</h2>
@@ -43,588 +36,288 @@ page.title=Signing Your Applications
 </div>
 </div>
 
-<p>The Android system requires that all installed applications be digitally signed with a
-certificate whose private key is held by the application's developer. The Android system uses the
-certificate as a means of identifying the author of an application and establishing trust
-relationships between applications. The certificate is not used to control which applications the
-user can install. The certificate does not need to be signed by a certificate authority: it is
-perfectly allowable, and typical, for Android applications to use self-signed certificates.</p>
-
-<p>The important points to understand about signing Android applications are:</p>
-
-<ul>
-  <li>All applications <em>must</em> be signed. The system will not install an application
-on an emulator or a device if it is not signed.</li>
-  <li>To test and debug your application, the build tools sign your application with a special debug
-    key that is created by the Android SDK build tools.</li>
-  <li>When you are ready to release your application for end-users, you must sign it with a suitable
-    private key. You cannot publish an application that is signed with the debug key generated
-    by the SDK tools.</li>
-  <li>You can use self-signed certificates to sign your applications. No certificate authority is
-    needed.</li>
-  <li>The system tests a signer certificate's expiration date only at install time. If an
-application's signer certificate expires after the application is installed, the application
-will continue to function normally.</li>
-  <li>You can use standard tools &mdash; Keytool and Jarsigner &mdash; to generate keys and
-sign your application {@code .apk} files.</li>
-  <li>After you sign your application for release, we recommend that you use the
-    <code>zipalign</code> tool to optimize the final APK package.</li>
-</ul>
 
-<p>The Android system will not install or run an application that is not signed appropriately. This
-applies wherever the Android system is run, whether on an actual device or on the emulator.
-For this reason, you must <a href="#setup">set up signing</a> for your application before you can
-run it or debug it on an emulator or device.</p>
-
-<h2 id="signing">Signing Process</h3>
-
-<p>The Android build process signs your application differently depending on which build mode you
-use to build your application. There are two build modes: <em>debug mode</em> and <em>release
-mode</em>. You use debug mode when you are developing and testing your application. You use
-release mode when you want to build a release version of your application that you can
-distribute directly to users or publish on an application marketplace such as Google Play.</p>
-
-<p>When you build in <em>debug mode</em> the Android SDK build tools use the Keytool utility
-(included in the JDK) to create a debug key. Because the SDK build tools created the debug key,
-they know the debug key's alias and password. Each time you compile your application in debug mode,
-the build tools use the debug key along with the Jarsigner utility (also included in the JDK) to
-sign your application's <code>.apk</code> file. Because the alias and password are known to the SDK
-build tools, the tools don't need to prompt you for the debug key's alias and password each time
-you compile.</p>
-
-<p>When you build in <em>release mode</em> you use your own private key to sign your application. If
-you don't have a private key, you can use the Keytool utility to create one for you. When you
-compile your application in release mode, the build tools use your private key along with the
-Jarsigner utility to sign your application's <code>.apk</code> file. Because the certificate and
-private key you use are your own, you must provide the password for the keystore and key alias.</p>
-
-<p>The debug signing process happens automatically when you run or debug your application using
-Eclipse with the ADT plugin. Debug signing also happens automatically when you use the Ant build
-script with the <code>debug</code> option. You can automate the release signing process by using the
-Eclipse Export Wizard or by modifying the Ant build script and building with the
-<code>release</code> option.</p>
-
-<h2 id="strategies">Signing Strategies</h2>
-
-<p>Some aspects of application signing may affect how you approach the development
-of your application, especially if you are planning to release multiple
-applications. </p>
-
-<p>In general, the recommended strategy for all developers is to sign
-all of your applications with the same certificate, throughout the expected
-lifespan of your applications. There are several reasons why you should do so: </p>
+<p>Android requires that all apps be digitally signed with a certificate before they can be
+installed. Android uses this certificate to identify the author of an app, and the certificate
+does not need to be signed by a certificate authority. Android apps often use self-signed
+certificates. The app developer holds the certificate's private key.</p>
 
-<ul>
-<li>Application upgrade &ndash; As you release updates to your application, you
-must continue to sign the updates with the same certificate or set of certificates,
-if you want users to be able to upgrade seamlessly to the new version. When
-the system is installing an update to an application, it compares the
-certificate(s) in the new version with those in the existing version. If the
-certificates match exactly, including both the certificate data and order, then
-the system allows the update. If you sign the new version without using matching
-certificates, you must also assign a different package name to the
-application &mdash; in this case, the user installs the new version as a
-completely new application. </li>
-
-<li>Application modularity &ndash; The Android system allows applications that
-are signed by the same certificate to run in the same process, if the
-applications so requests, so that the system treats them as a single application.
-In this way you can deploy your application in modules, and users can update
-each of the modules independently if needed.</li>
-
-<li>Code/data sharing through permissions &ndash; The Android system provides
-signature-based permissions enforcement, so that an application can expose
-functionality to another application that is signed with a specified
-certificate. By signing multiple applications with the same certificate and
-using signature-based permissions checks, your applications can share code and
-data in a secure manner. </li>
 
-</ul>
+<h2 id="overview">Signing Overview</h2>
 
-<p>Another important consideration in determining your signing strategy is
-how to set the validity period of the key that you will use to sign your
-applications.</p>
+<p>You can sign an app in debug or release mode. You sign your app in debug mode during development
+and in release mode when you are ready to distribute your app. The Android SDK generates a
+certificate to sign apps in debug mode. To sign apps in release mode, you need to generate
+your own certificate.</p>
 
-<ul>
-<li>If you plan to support upgrades for a single application, you should ensure
-that your key has a validity period that exceeds the expected lifespan of
-that application. A validity period of 25 years or more is recommended.
-When your key's validity period expires, users will no longer be
-able to seamlessly upgrade to new versions of your application.</li>
-
-<li>If you will sign multiple distinct applications with the same key,
-you should ensure that your key's validity period exceeds the expected
-lifespan of <em>all versions of all of the applications</em>, including
-dependent applications that may be added to the suite in the future. </li>
-
-<li>If you plan to publish your application(s) on Google Play, the
-key you use to sign the application(s) must have a validity period
-ending after 22 October 2033. Google Play enforces this requirement
-to ensure that users can seamlessly upgrade applications when
-new versions are available. </li>
-</ul>
+<h3 id="debug-mode">Signing in Debug Mode</h3>
 
-<p>As you design your application, keep these points in mind and make sure to
-use a <a href="#cert">suitable certificate</a> to sign your applications. </p>
+<p>In debug mode, you sign your app with a debug certificate generated by the Android SDK tools.
+This certificate has a private key with a known password, so you can run and debug your app
+without typing the password every time you make a change to your project.</p>
 
-<h2 id="setup">Basic Setup for Signing</h2>
+<p>Android Studio and the ADT plugin for Eclipse sign your app in debug mode automatically when
+you run or debug your project from the IDE.</p>
 
-<p>Before you begin, make sure that the Keytool utility and Jarsigner utility are available to
-the SDK build tools. Both of these tools are available in the JDK. In most cases, you can tell
-the SDK build tools how to find these utilities by setting your <code>JAVA_HOME</code> environment
-variable so it references a suitable JDK. Alternatively, you can add the JDK version of Keytool and
-Jarsigner to your <code>PATH</code> variable.</p>
+<p>You can run and debug an app signed in debug mode on the emulator and on devices connected
+to your development manchine through USB, but you cannot distribute an app signed in debug
+mode.</p>
 
-<p>If you are developing on a version of Linux that originally came with GNU Compiler for
-Java, make sure that the system is using the JDK version of Keytool, rather than the gcj
-version. If Keytool is already in your <code>PATH</code>, it might be pointing to a symlink at
-<code>/usr/bin/keytool</code>. In this case, check the symlink target to be sure it points
-to the Keytool in the JDK.</p>
+<p>For more information about how to build and run apps in debug mode, see
+<a href="{@docRoot}tools/building/index.html">Building and Running</a>.</p>
 
-<h2 id="debugmode">Signing in Debug Mode</h2>
+<h3 id="release-mode">Signing in Release Mode</h3>
 
-<p>The Android build tools provide a debug signing mode that makes it easier for you
-to develop and debug your application, while still meeting the Android system
-requirement for signing your APK.
-When using debug mode to build your app, the SDK tools invoke Keytool to automatically create
-a debug keystore and key. This debug key is then used to automatically sign the APK, so
-you do not need to sign the package with your own key.</p>
+<p>In release mode, you sign your app with your own certificate:</p>
 
-<p>The SDK tools create the debug keystore/key with predetermined names/passwords:</p>
-<ul>
-<li>Keystore name: "debug.keystore"</li>
-<li>Keystore password: "android"</li>
-<li>Key alias: "androiddebugkey"</li>
-<li>Key password: "android"</li>
-<li>CN: "CN=Android Debug,O=Android,C=US"</li>
-</ul>
-
-<p>If necessary, you can change the location/name of the debug keystore/key or
-supply a custom debug keystore/key to use. However, any custom debug
-keystore/key must use the same keystore/key names and passwords as the default
-debug key (as described above). (To do so in Eclipse/ADT, go to
-<strong>Windows</strong> &gt; <strong>Preferences</strong> &gt;
-<strong>Android</strong> &gt; <strong>Build</strong>.) </p>
-
-<p class="caution"><strong>Caution:</strong> You <em>cannot</em> release your application
-to the public when signed with the debug certificate.</p>
+<ol>
+<li><em>Create a keystore.</em> A <strong>keystore</strong> is a binary file that contains a
+set of private keys. You must keep your keystore in a safe and secure place.</li>
+<li><em>Create a private key.</em> A <strong>private key</strong> represents the entity to
+be identified with the app, such as a person or a company.</li>
+<li><em>Build your project</em>. Generate an unsigned APK for your app.</li>
+<li><em>Sign your app.</em> Use your private key to generate a signed version of your APK.</li>
+</ol>
 
-<h3>Eclipse Users</h3>
+<p>After you complete this process, you can distribute your app and publish it on Google Play.</p>
 
-<p>If you are developing in Eclipse/ADT (and have set up Keytool and Jarsigner as described above in
-<a href="#setup">Basic Setup for Signing</a>),
-signing in debug mode is enabled by default. When you run or debug your
-application, ADT signs the {@code .apk} file with the debug certificate, runs {@code zipalign} on
-the package, then installs it on
-the selected emulator or connected device. No specific action on your part is needed,
-provided ADT has access to Keytool.</p>
+<p class="warning"><strong>Warning:</strong> Keep your keystore and private key in a safe and
+secure place, and ensure that you have secure backups of them. If you publish an app to Google
+Play and then lose the key with which you signed your app, you will not be able to publish
+any updates to your app, since you must always sign all versions of your app with the same
+key.</p>
 
-<h3>Ant Users</h3>
+<p>The rest of this document provides detailed instructions about how to generate a private
+key and sign your apps in release mode with Android Studio and with the ADT plugin for Eclipse.</p>
 
-<p>If you are using Ant to build your {@code .apk} file, debug signing mode
-is enabled by using the <code>debug</code> option with the <code>ant</code> command
-(assuming that you are using a <code>build.xml</code> file generated by the
-<code>android</code> tool). When you run <code>ant debug</code> to
-compile your app, the build script generates a keystore/key and signs the APK for you.
-The script then also aligns the APK with the <code>zipalign</code> tool.
-No other action on your part is needed. Read
-<a href="{@docRoot}tools/building/building-cmdline.html#DebugMode">Building and Running Apps
-on the Command Line</a> for more information.</p>
+<h3 id="wear-apps">Signing Android Wear Apps</h3>
 
+<p>When publishing Android Wear apps, you package the wearable app inside of a handheld app,
+because users cannot browse and install apps directly on the wearable. Both apps must be signed.
+For more information on packaging and signing Android Wear apps, see
+<a href="{@docRoot}training/wearables/apps/packaging.html">Packaging Wearable Apps</a>.</p>
 
-<h3 id="debugexpiry">Expiry of the Debug Certificate</h3>
 
-<p>The self-signed certificate used to sign your application in debug mode (the default on
-Eclipse/ADT and Ant builds) will have an expiration date of 365 days from its creation date.</p>
+<h2 id="studio">Signing Your App in Android Studio</h2>
 
-<p>When the certificate expires, you will get a build error. On Ant builds, the error
-looks like this:</p>
+<p>To sign your app in release mode in Android Studio, follow these steps:</p>
 
-<pre>debug:
-[echo] Packaging bin/samples-debug.apk, and signing it with a debug key...
-[exec] Debug Certificate expired on 8/4/08 3:43 PM</pre>
+<ol>
+<li>On the menu bar, click <strong>Build</strong> &gt; <strong>Generate Signed APK</strong>.</li>
+<li><p>On the <em>Generate Signed APK Wizard</em> window, click <strong>Create new</strong> to create
+a new keystore.</p><p>If you already have a keystore, go to step 4.</p></li>
+<li><p>On the <em>New Key Store</em> window, provide the required information as shown
+in figure 1.</p><p>Your key should be valid for at least 25 years, so you can sign app updates
+with the same key through the lifespan of your app.</p>
+<img src="{@docRoot}images/tools/signstudio2.png" alt=""
+     width="416" height="364" style="margin-top:15px"/>
+<p class="img-caption"><strong>Figure 1</strong>. Create a new keystore in Android Studio.</p>
+</li>
+<li><p>On the <em>Generate Signed APK Wizard</em> window, select a keystore, a private key, and enter
+the passwords for both. Then click <strong>Next</strong>.</p>
+<img src="{@docRoot}images/tools/signstudio1.png" alt=""
+     width="349" height="232" style="margin-top:15px"/>
+<p class="img-caption"><strong>Figure 2</strong>. Select a private key in Android Studio.</p>
+</li>
+<li><p>On the next window, select a destination for the signed APK and click
+<strong>Finish</strong>.</p>
+<img src="{@docRoot}images/tools/signstudio3.png" alt=""
+     width="350" height="175" style="margin-top:15px"/>
+<p class="img-caption"><strong>Figure 3</strong>. Generate a signed APK in Android Studio.</p>
+</li>
+</ol>
 
-<p>In Eclipse/ADT, you will see a similar error in the Android console.</p>
+<h3 id="sign-auto">Automatically Signing Your App</h3>
 
-<p>To fix this problem, simply delete the <code>debug.keystore</code> file.
-The default storage location for AVDs is in <code>~/.android/</code> on OS X and Linux,
-in <code>C:\Documents and Settings\&lt;user>\.android\</code> on Windows XP, and in
-<code>C:\Users\&lt;user>\.android\</code> on Windows Vista and Windows 7.</p>
+<p>In Android Studio, you can configure your project to sign your release APK automatically
+during the build process:</p>
 
+<ol>
+<li>On the project browser, right click on your app and select <strong>Open Module
+Settings</strong>.</li>
+<li>On the <em>Project Structure</em> window, select your app's module under <em>Modules</em>.</li>
+<li>Click on the <strong>Signing</strong> tab.</li>
+<li><p>Select your keystore file, enter a name for this signing configuration (as you may create
+more than one), and enter the required information.</p>
+<img src="{@docRoot}images/tools/signstudio10.png" alt=""
+     width="623" height="372" style="margin-top:15px"/>
+<p class="img-caption"><strong>Figure 4</strong>. Create a signing configuration in Android Studio.</p>
+</li>
+<li>Click on the <strong>Build Types</strong> tab.</li>
+<li>Select the <strong>release</strong> build.</li>
+<li><p>Under <em>Signing Config</em>, select the signing configuration you just created.</p>
+<img src="{@docRoot}images/tools/signstudio11.png" alt=""
+     width="623" height="372" style="margin-top:15px"/>
+<p class="img-caption"><strong>Figure 5</strong>. Select a signing configuration in Android Studio.</p>
+</li>
+<li>Click <strong>OK</strong>.</li>
+</ol>
 
-<p>The next time you build, the build tools will regenerate a new keystore and debug key.</p>
+<p>You can also specify your signing settings in Gradle configuration files. For more information,
+see <a href="{@docRoot}sdk/installing/studio-build.html#configureSigning">Signing settings</a>.</p>
 
-<p>Note that, if your development machine is using a non-Gregorian locale, the build
-tools may erroneously generate an already-expired debug certificate, so that you get an
-error when trying to compile your application. For workaround information, see the
-troubleshooting topic <a href="{@docRoot}resources/faq/troubleshooting.html#signingcalendar">
-I&nbsp;can't&nbsp;compile my app because the build tools generated an expired debug
-certificate</a>. </p>
 
+<h2 id="adt">Signing Your App with the ADT Plugin for Eclipse</h2>
 
-<h2 id="releasemode">Signing in Release Mode</h2>
+<p>To sign your app in release mode in ADT, follow these steps:</p>
 
-<p>When your application is ready for release to other users, you must:</p>
 <ol>
-  <li><a href="#cert">Obtain a suitable private key</a></li>
-  <li><a href="#releasecompile">Compile the application in release mode</a></li>
-  <li><a href="#signapp">Sign your application with your private key</a></li>
-  <li><a href="#align">Align the final APK package</a></li>
+<li>Select the project in the Package Explorer and select <strong>File</strong> >
+<strong>Export</strong>.</li>
+<li>On the <em>Export</em> window, select <strong>Export Android Application</strong> and click
+<strong>Next</strong>.</li>
+<li>On the <em>Export Android Application</em> window, select the project you want to sign and
+click <strong>Next</strong>.</li>
+<li>
+<p>On the next window, enter the location to create a keystore and a keystore password. If you
+already have a keystore, select <strong>Use existing keystore</strong>, enter your keystore's
+location and password, and go to step 6.</p>
+<img src="{@docRoot}images/tools/signadt3.png" alt=""
+     width="488" height="270" style="margin-top:15px"/>
+<p class="img-caption"><strong>Figure 6</strong>. Select a keystore in ADT.</p>
+</li>
+<li><p>On the next window, provide the required information as shown in figure 5.<p>
+<p>Your key should be valid for at least 25 years, so you can sign app updates with the same key
+through the lifespan of your app.</p>
+<img src="{@docRoot}images/tools/signadt4.png" alt=""
+     width="488" height="448" style="margin-top:15px"/>
+<p class="img-caption"><strong>Figure 7</strong>. Create a private key in ADT.</p>
+</li>
+<li><p>On the next window, select the location to export the signed APK.</p>
+<img src="{@docRoot}images/tools/signadt5.png" alt=""
+     width="488" height="217" style="margin-top:15px"/>
+<p class="img-caption"><strong>Figure 8</strong>. Export the signed APK in ADT.</p>
+</li>
 </ol>
 
-<p>If you are developing in Eclipse with the ADT plugin, you can use the Export Wizard
-to perform the compile, sign, and align procedures. The Export Wizard even allows you to
-generate a new keystore and private key in the process. So if you use Eclipse, you can
-skip to <a href="#ExportWizard">Compile and sign with Eclipse ADT</a>.</p>
-
 
+<h2 id="considerations">Signing Considerations</h2>
 
-<h3 id="cert">1. Obtain a suitable private key</h3>
-
-<p>In preparation for signing your application, you must first ensure that
-you have a suitable private key with which to sign. A suitable private
-key is one that:</p>
+<p>You should sign all of your apps with the same certificate throughout the expected lifespan
+of your applications. There are several reasons why you should do so:</p>
 
 <ul>
-<li>Is in your possession</li>
-<li>Represents the personal, corporate, or organizational entity to be identified
-with the application</li>
-<li>Has a validity period that exceeds the expected lifespan of the application
-or application suite. A validity period of more than 25 years is recommended.
-<p>If you plan to publish your application(s) on Google Play, note that a
-validity period ending after 22 October 2033 is a requirement. You can not upload an
-application if it is signed with a key whose validity expires before that date.
-</p></li>
-<li>Is not the debug key generated by the Android SDK tools. </li>
+<li>App upgrade: When the system is installing an update to an app, it compares the certificate(s)
+in the new version with those in the existing version. The system allows the update if the
+certificates match. If you sign the new version with a different certificate, you must assign a
+different package name to the application&mdash;in this case, the user installs the new version as
+a completely new application.</li>
+<li>App modularity: Android allows apps signed by the same certificate to run in the same process,
+if the applications so requests, so that the system treats them as a single application. In this
+way you can deploy your app in modules, and users can update each of the modules independently.</li>
+<li>Code/data sharing through permissions: Android provides signature-based permissions
+enforcement, so that an app can expose functionality to another app that is signed with a
+specified certificate. By signing multiple apps with the same certificate and using
+signature-based permissions checks, your apps can share code and data in a secure manner.</li>
 </ul>
 
-<p>The key may be self-signed. If you do not have a suitable key, you must
-generate one using Keytool. Make sure that you have Keytool available, as described
-in <a href="#setup">Basic Setup</a>.</p>
-
-<p>To generate a self-signed key with Keytool, use the <code>keytool</code>
-command and pass any of the options listed below (and any others, as
-needed). </p>
-
-<p class="warning"><strong>Warning:</strong> Keep your private key secure.
-Before you run Keytool, make sure to read
-<a href="#secure-key">Securing Your Private Key</a> for a discussion of how to keep
-your key secure and why doing so is critically important to you and to users. In
-particular, when you are generating your key, you should select strong passwords
-for both the keystore and key.</p>
-
-<p class="warning"><strong>Warning:</strong> Keep the keystore file you generate with Keytool
-in a safe, secure place. You must use the same key to sign future versions of your application. If
-you republish your app with a new key, Google Play will consider it a new app. For more information
-on settings that must remain constant over the life of your app, see the Android Developer Blog post
-<a href="http://android-developers.blogspot.com/2011/06/things-that-cannot-change.html">Things
-That Cannot Change</a>.</p>
-
-<table>
-<tr>
-<th>Keytool Option</th>
-<th>Description</th>
-</tr>
-<tr>
-<td><code>-genkey</code></td><td>Generate a key pair (public and private
-keys)</td>
-</tr>
-<tr>
-<td><code>-v</code></td><td>Enable verbose output.</td>
-</tr>
-<tr>
-<td><code>-alias &lt;alias_name&gt;</code></td><td>An alias for the key. Only
-the first 8 characters of the alias are used.</td>
-</tr>
-<tr>
-<td><code>-keyalg &lt;alg&gt;</code></td><td>The encryption algorithm to use
-when generating the key. Both DSA and RSA are supported.</td>
-</tr>
-<tr>
-<td><code>-keysize &lt;size&gt;</code></td><td>The size of each generated key
-(bits). If not supplied, Keytool uses a default key size of 1024 bits. In
-general, we recommend using a key size of 2048 bits or higher. </td>
-</tr>
-<tr>
-<td><code>-dname &lt;name&gt;</code></td><td><p>A Distinguished Name that describes
-who created the key. The value is used as the issuer and subject fields in the
-self-signed certificate. </p><p>Note that you do not need to specify this option
-in the command line. If not supplied, Jarsigner prompts you to enter each
-of the Distinguished Name fields (CN, OU, and so on).</p></td>
-</tr>
-<tr>
-<td><code>-keypass &lt;password&gt;</code></td><td><p>The password for the
-key.</p> <p>As a security precaution, do not include this option in your command
-line. If not supplied, Keytool prompts you to enter the password. In this way,
-your password is not stored in your shell history.</p></td>
-</tr>
-<tr>
-<td><code>-validity &lt;valdays&gt;</code></td><td><p>The validity period for the
-key, in days. </p><p><strong>Note:</strong> A value of 10000 or greater is recommended.</p></td>
-</tr>
-<tr>
-<td><code>-keystore&nbsp;&lt;keystore-name&gt;.keystore</code></td><td>A name
-for the keystore containing the private key.</td>
-</tr>
-<tr>
-<td><code>-storepass &lt;password&gt;</code></td><td><p>A password for the
-keystore.</p><p>As a security precaution, do not include this option in your
-command line. If not supplied, Keytool prompts you to enter the password. In
-this way, your password is not stored in your shell history.</p></td>
-</tr>
-</table>
-
-<p>Here's an example of a Keytool command that generates a private key:</p>
-
-<pre>$ keytool -genkey -v -keystore my-release-key.keystore
--alias alias_name -keyalg RSA -keysize 2048 -validity 10000</pre>
-
-<p>Running the example command above, Keytool prompts you to provide
-passwords for the keystore and key, and to provide the Distinguished
-Name fields for your key. It then generates the keystore as a file called
-<code>my-release-key.keystore</code>. The keystore and key are
-protected by the passwords you entered. The keystore contains
-a single key, valid for 10000 days. The alias is a name that you &mdash;
-will use later, to refer to this keystore when signing your application. </p>
-
-<p>For more information about Keytool, see the documentation at
-<a
-href="http://docs.oracle.com/javase/6/docs/technotes/tools/windows/keytool.html">
-http://docs.oracle.com/javase/6/docs/technotes/tools/windows/keytool.html</a></p>
-
-
-
-<h3 id="releasecompile">2. Compile the application in release mode</h3>
-
-<p>In order to release your application to users, you must compile it in release mode.
-In release mode, the compiled application is not signed by default and you will need
-to sign it with your private key.</p>
-
-<p class="caution"><strong>Caution:</strong>
-You can not release your application unsigned, or signed with the debug key.</p>
-
-<h4>With Eclipse</h4>
-
-<p>To export an <em>unsigned</em> APK from Eclipse, right-click the project in the Package
-Explorer and select <strong>Android Tools</strong> > <strong>Export Unsigned Application
-Package</strong>. Then specify the file location for the unsigned APK.
-(Alternatively, open your <code>AndroidManifest.xml</code> file in Eclipse, select
-the <strong>Manifest</strong> tab, and click <strong>Export an unsigned APK</strong>.)</p>
-
-<p>Note that you can combine the compiling and signing steps with the Export Wizard. See
-<a href="#ExportWizard">Compiling and signing with Eclipse ADT</a>.</p>
-
-<h4>With Ant</h4>
-
-<p>If you are using Ant, you can enable release mode by using the <code>release</code> option
-with the <code>ant</code> command. For example, if you are running Ant from the
-directory containing your {@code build.xml} file, the command would look like this:</p>
-
-<pre>$ ant release</pre>
-
-<p>By default, the build script compiles the application APK without signing it. The output file
-in your project {@code bin/} will be <code><em>&lt;your_project_name></em>-unsigned.apk</code>.
-Because the application APK is still unsigned, you must manually sign it with your private
-key and then align it using {@code zipalign}.</p>
-
-<p>However, the Ant build script can also perform the signing
-and aligning for you, if you have provided the path to your keystore and the name of
-your key alias in the project's {@code ant.properties} file. With this information provided,
-the build script will prompt you for your keystore and alias password when you perform
-<code>ant release</code>, it will sign the package and then align it. The final output
-file in {@code bin/} will instead be
-<code><em>&lt;your_project_name></em>-release.apk</code>. With these steps
-automated for you, you're able to skip the manual procedures below (steps 3 and 4).
-To learn how to specify your keystore and alias in the {@code ant.properties} file,
-see <a href="{@docRoot}tools/building/building-cmdline.html#ReleaseMode">
-Building and Running Apps on the Command Line</a>.</p>
-
-
-
-<h3 id="signapp">3. Sign your application with your private key</h3>
-
-<p>When you have an application package that is ready to be signed, you can do sign it
-using the Jarsigner tool. Make sure that you have Jarsigner available on your
-machine, as described in <a href="#setup">Basic Setup</a>. Also, make sure that
-the keystore containing your private key is  available.</p>
-
-<p>To sign your application, you run Jarsigner, referencing both the
-application's APK and the keystore containing the private key with which to
-sign the APK. The table below shows the options you could use. </p>
-
-<table>
-<tr>
-<th>Jarsigner Option</th>
-<th>Description</th>
-</tr>
-<tr>
-<td><code>-keystore&nbsp;&lt;keystore-name&gt;.keystore</code></td><td>The name of
-the keystore containing your private key.</td>
-</tr>
-<tr>
-<td><code>-verbose</code></td><td>Enable verbose output.</td>
-</tr>
-<tr>
-<td><code>-sigalg</code></td><td>The name of the signature algorithim to use in signing the APK.
-Use the value {@code SHA1withRSA}.</td>
-</tr>
-<tr>
-<td><code>-digestalg</code></td><td>The message digest algorithim to use in processing the entries
-of an APK. Use the value {@code SHA1}.</td>
-</tr>
-<tr>
-<td><code>-storepass &lt;password&gt;</code></td><td><p>The password for the
-keystore. </p><p>As a security precaution, do not include this option
-in your command line unless you are working at a secure computer.
-If not supplied, Jarsigner prompts you to enter the password. In this
-way, your password is not stored in your shell history.</p></td>
-</tr>
-<tr>
-<td><code>-keypass &lt;password&gt;</code></td><td><p>The password for the private
-key. </p><p>As a security precaution, do not include this option
-in your command line unless you are working at a secure computer.
-If not supplied, Jarsigner prompts you to enter the password. In this
-way, your password is not stored in your shell history.</p></td>
-</tr>
-</table>
-
-<p>Here's how you would use Jarsigner to sign an application package called
-<code>my_application.apk</code>, using the example keystore created above.
-</p>
-
-<pre>$ jarsigner -verbose -sigalg SHA1withRSA -digestalg SHA1 -keystore my-release-key.keystore
-my_application.apk alias_name</pre>
-
-<p>Running the example command above, Jarsigner prompts you to provide
-passwords for the keystore and key. It then modifies the APK
-in-place, meaning the APK is now signed. Note that you can sign an
-APK multiple times with different keys.</p>
-
-<p class="caution"><strong>Caution:</strong> As of JDK 7, the default signing algorithim has
-changed, requiring you to specify the signature and digest algorithims ({@code -sigalg} and {@code
--digestalg}) when you sign an APK.</p>
-
-<p>To verify that your APK is signed, you can use a command like this:</p>
-
-<pre>$ jarsigner -verify my_signed.apk</pre>
-
-<p>If the APK is signed properly, Jarsigner prints "jar verified".
-If you want more details, you can try one of these commands:</p>
-
-<pre>$ jarsigner -verify -verbose my_application.apk</pre>
-
-<p>or</p>
-
-<pre>$ jarsigner -verify -verbose -certs my_application.apk</pre>
-
-<p>The command above, with the <code>-certs</code> option added, will show you the
-"CN=" line that describes who created the key.</p>
-
-<p class="note"><strong>Note:</strong> If you see "CN=Android Debug", this means the APK was
-signed with the debug key generated by the Android SDK. If you intend to release
-your application, you must sign it with your private key instead of the debug
-key.</p>
-
-<p>For more information about Jarsigner, see the documentation at
-<a href="http://docs.oracle.com/javase/6/docs/technotes/tools/windows/jarsigner.html">
-http://docs.oracle.com/javase/6/docs/technotes/tools/windows/jarsigner.html</a></p>
-
+<p>If you plan to support upgrades for an app, ensure that your key has a validity
+period that exceeds the expected lifespan of that app. A validity period of 25 years or more is
+recommended. When your key's validity period expires, users will no longer be able to seamlessly
+upgrade to new versions of your application.</p>
 
-<h3 id="align">4. Align the final APK package</h3>
+<p>If you plan to publish your apps on Google Play, the key you use to sign these apps must have
+a validity period ending after 22 October 2033. Google Play enforces this requirement to ensure
+that users can seamlessly upgrade apps when new versions are available.</p>
 
-<p>Once you have signed the APK with your private key, run <code>zipalign</code> on the file.
-This tool ensures that all uncompressed data starts with a particular byte alignment,
-relative to the start of the file. Ensuring alignment at 4-byte boundaries provides
-a performance optimization when installed on a device. When aligned, the Android
-system is able to read files with {@code mmap()}, even if
-they contain binary data with alignment restrictions, rather than copying all
-of the data from the package. The benefit is a reduction in the amount of
-RAM consumed by the running application.</p>
 
-<p>The <code>zipalign</code> tool is provided with the Android SDK, inside the
-<code>tools/</code> directory. To align your signed APK, execute:</p>
-
-<pre>$ zipalign -v 4 <em>your_project_name</em>-unaligned.apk <em>your_project_name</em>.apk</pre>
-
-<p>The {@code -v} flag turns on verbose output (optional). {@code 4} is the
-byte-alignment (don't use anything other than 4). The first file argument is
-your signed {@code .apk} file (the input) and the second file is the destination {@code .apk} file
-(the output). If you're overriding an existing APK, add the {@code -f} flag.</p>
+<h2 id="secure-key">Securing Your Private Key</h2>
 
-<p class="caution"><strong>Caution:</strong> Your input APK must be signed with your
-private key <strong>before</strong> you optimize the package with {@code zipalign}.
-If you sign it after using {@code zipalign}, it will undo the alignment.</p>
+<p>Maintaining the security of your private key is of critical importance, both to you and to
+the user. If you allow someone to use your key, or if you leave your keystore and passwords in
+an unsecured location such that a third-party could find and use them, your authoring identity
+and the trust of the user are compromised.</p>
 
-<p>For more information, read about the
-<a href="{@docRoot}tools/help/zipalign.html">zipalign</a> tool.
+<p>If a third party should manage to take your key without your knowledge or permission, that
+person could sign and distribute apps that maliciously replace your authentic apps or corrupt
+them. Such a person could also sign and distribute apps under your identity that attack
+other apps or the system itself, or corrupt or steal user data.</p>
 
+<p>Your private key is required for signing all future versions of your app. If you lose or
+misplace your key, you will not be able to publish updates to your existing appn. You cannot
+regenerate a previously generated key.</p>
 
-<h3 id="ExportWizard">Compile and sign with Eclipse ADT</h3>
+<p>Your reputation as a developer entity depends on your securing your private key properly, at
+all times, until the key is expired. Here are some tips for keeping your key secure:</p>
 
-<p>If you are using Eclipse with the ADT plugin, you can use the Export Wizard to
-export a <em>signed</em> APK (and even create a new keystore,
-if necessary). The Export Wizard performs all the interaction with
-the Keytool and Jarsigner for you, which allows you to sign the package using a GUI
-instead of performing the manual procedures to compile, sign,
-and align, as discussed above. Once the wizard has compiled and signed your package,
-it will also perfom package alignment with {@code zipalign}.
-Because the Export Wizard uses both Keytool and Jarsigner, you should
-ensure that they are accessible on your computer, as described above
-in the <a href="#setup">Basic Setup for Signing</a>.</p>
+<ul>
+<li>Select strong passwords for the keystore and key.</li>
+<li>Do not give or lend anyone your private key, and do not let unauthorized persons know your
+keystore and key passwords.</li>
+<li>Keep the keystore file containing your private key in a safe, secure place.</li>
+</ul>
 
-<p>To create a signed and aligned APK in Eclipse:</p>
+<p>In general, if you follow common-sense precautions when generating, using, and storing
+your key, it will remain secure.</p>
 
-<ol>
-  <li>Select the project in the Package
-Explorer and select <strong>File > Export</strong>.</li>
-  <li>Open the Android folder, select Export Android Application,
-  and click <strong>Next</strong>.
-  <p>The Export Android Application wizard now starts, which will
-  guide you through the process of signing your application,
-  including steps for selecting the private key with which to sign the APK
-  (or creating a new keystore and private key).</p>
-  <li>Complete the Export Wizard and your application will be compiled,
-  signed, aligned, and ready for distribution.</li>
-</ol>
 
+<h2 id="expdebug">Expiry of the Debug Certificate</h2>
 
+<p>The self-signed certificate used to sign your application in debug mode has an expiration date
+of 365 days from its creation date. When the certificate expires, you will get a build error.</p>
 
-<h2 id="secure-key">Securing Your Private Key</h2>
+<p>To fix this problem, simply delete the <code>debug.keystore</code> file. The default storage
+location is in <code>~/.android/</code> on OS X and Linux, in <code>C:\Documents and
+Settings\&lt;user&gt;\.android\</code> on Windows XP, and in
+<code>C:\Users\&lt;user&gt;\.android\</code> on Windows Vista and Windows 7.</p>
 
-<p>Maintaining the security of your private key is of critical importance, both
-to you and to the user. If you allow someone to use your key, or if you leave
-your keystore and passwords in an unsecured location such that a third-party
-could find and use them, your authoring identity and the trust of the user
-are compromised. </p>
+<p>The next time you build, the build tools will regenerate a new keystore and debug key.</p>
 
-<p>If a third party should manage to take your key without your knowledge or
-permission, that person could sign and distribute applications that maliciously
-replace your authentic applications or corrupt them. Such a person could also
-sign and distribute applications under your identity that attack other
-applications or the system itself, or corrupt or steal user data. </p>
+<p>Note that, if your development machine is using a non-Gregorian locale, the build tools may
+erroneously generate an already-expired debug certificate, so that you get an error when trying
+to compile your application. For workaround information, see the troubleshooting topic
+<a href="{@docRoot}resources/faq/troubleshooting.html#signingcalendar">I can't compile my app
+because the build tools generated an expired debug certificate</a>.</p>
 
-<p>Your private key is required for signing all future versions of your application. If you lose or
-misplace your key, you will not be able to publish updates to your existing application. You cannot
-regenerate a previously generated key.</p>
 
-<p>Your reputation as a developer entity depends on your securing your private
-key properly, at all times, until the key is expired. Here are some tips for
-keeping your key secure: </p>
+<h2 id="signing-manually">Signing Your App Manually</h2>
 
-<ul>
-<li>Select strong passwords for the keystore and key.</li>
-<li>When you generate your key with Keytool, <em>do not</em> supply the
-<code>-storepass</code> and <code>-keypass</code> options at the command line.
-If you do so, your passwords will be available in your shell history,
-which any user on your computer could access.</li>
-<li>Similarly, when signing your applications with Jarsigner,
-<em>do not</em> supply the <code>-storepass</code> and <code>-keypass</code>
-options at the command line. </li>
-<li>Do not give or lend anyone your private key, and do not let unauthorized
-persons know your keystore and key passwords.</li>
-<li>Keep the keystore file containing your private key that you <a href="#cert">generate with the
-Keytool</a> in a safe, secure place.</li>
-</ul>
+<p>You do not need Android Studio or the ADT plugin for Eclipse to sign your app. You can sign
+your app from the command line using standard tools from the Android SDK and the JDK. To sign
+an app in release mode from the command line:</p>
 
-<p>In general, if you follow common-sense precautions when generating, using,
-and storing your key, it will remain secure. </p>
+<ol>
+<li>
+  <p>Generate a private key using
+  <code><a href="http://docs.oracle.com/javase/6/docs/technotes/tools/solaris/keytool.html">keytool</a></code>.
+  For example:</p>
+<pre>
+$ keytool -genkey -v -keystore my-release-key.keystore
+-alias alias_name -keyalg RSA -keysize 2048 -validity 10000
+</pre>
+  <p>This example prompts you for passwords for the keystore and key, and to provide the
+  Distinguished Name fields for your key. It then generates the keystore as a file called
+  <code>my-release-key.keystore</code>. The keystore contains a single key, valid for 10000 days.
+  The alias is a name that you will use later when signing your app.</p>
+</li>
+<li style="margin-top:18px">
+  <p>Compile your app in release mode to obtain an unsigned APK.</p>
+</li>
+<li style="margin-top:18px">
+  <p>Sign your app with your private key using
+  <code><a href="http://docs.oracle.com/javase/6/docs/technotes/tools/windows/jarsigner.html">jarsigner</a></code>:
+  </p>
+<pre>
+$ jarsigner -verbose -sigalg SHA1withRSA -digestalg SHA1
+-keystore my-release-key.keystore my_application.apk alias_name
+</pre>
+  <p>This example prompts you for passwords for the keystore and key. It then modifies the APK
+  in-place to sign it. Note that you can sign an APK multiple times with different keys.</p>
+</li>
+<li style="margin-top:18px">
+  <p>Verify that your APK is signed. For example:</p>
+<pre>
+$ jarsigner -verify -verbose -certs my_application.apk
+</pre>
+</li>
+<li style="margin-top:18px">
+  <p>Align the final APK package using
+  <code><a href="{@docRoot}tools/help/zipalign.html">zipalign</a></code>.</p>
+<pre>
+$ zipalign -v 4 your_project_name-unaligned.apk your_project_name.apk
+</pre>
+  <p><code>zipalign</code> ensures that all uncompressed data starts with a particular byte
+  alignment relative to the start of the file, which reduces the amount of RAM consumed by an
+  app.</p>
+</li>
+</ol>