1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
|
page.title=Signing Your Applications
@jd:body
<div id="qv-wrapper">
<div id="qv">
<h2>Signing quickview</h2>
<ul>
<li>All Android apps <em>must</em> be signed</a></li>
<li>You can sign with a self-signed key</li>
<li>How you sign your apps is critical — 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="#overview">Overview</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 for Public Release</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>
<li><a href="#secure-key">Securing Your Private Key</a></li>
</ol>
<h2>See also</h2>
<ol>
<li><a href="{@docRoot}guide/publishing/versioning.html">Versioning Your Applications</a></li>
<li><a href="{@docRoot}guide/publishing/preparing.html">Preparing to Publish</a></li>
</ol>
</div>
</div>
<p>This document provides information about signing your Android applications prior to publishing them for mobile device users.</p>
<h2 id="overview">Overview</h2>
<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
that is not signed.</li>
<li>You can use self-signed certificates to sign your applications. No certificate authority
is needed.</li>
<li>When you are ready to release your application for end-users, you must sign it with a suitable private
key. You can not publish an application that is signed with the debug key generated
by the SDK tools.
</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 — Keytool and Jarsigner — to generate keys and
sign your application .apk files.</li>
<li>Once you have signed the application, 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 set up signing for your application before you will be able to
run or debug it on an emulator or device.</p>
<p>The Android SDK tools assist you in signing your applications when debugging. Both the ADT Plugin
for Eclipse and the Ant build tool offer two signing modes — <em>debug mode</em>
and <em>release mode</em>.
<ul>
<li>While developing and testing, you can compile in debug mode.
In debug mode, the build tools use the Keytool utility, included in the JDK, to create
a keystore and key with a known alias and password. At each compilation, the tools then use
the debug key to sign the application .apk file. Because the password is known, the tools
don't need to prompt you for the keystore/key password each time you compile.</li>
<li>When your application is ready for release, you must compile in release mode
and then sign the .apk <span style="color:red">with your private key</span>.
There are two ways to do this:
<ul>
<li>Using Keytool and Jarsigner in the command-line. In this approach,
you first compile your application to an <em>unsigned</em> .apk. You must then sign
the .apk manually with your private key
using Jarsigner (or similar tool). If you do not have a suitable private key already,
you can run Keytool manually to generate your own keystore/key and then sign your
application with Jarsigner.</li>
<li>Using the ADT Export Wizard. If you are developing in Eclipse with the ADT plugin,
you can use the Export Wizard to compile the application, generate a private key
(if necessary), and sign the .apk, all in a single process using the Export Wizard.
</li>
</ul>
</li>
</ul>
<p>Once your application is signed, don't forget to run {@code zipalign} on the APK
for additional optimization.</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>
<ul>
<li>Application upgrade – As you release upgrades to your
application, you will want to sign the upgrades with the same certificate, if you
want users to upgrade seamlessly to the new version. When the system is
installing an update to an application, if any of the certificates in the
new version match any of the certificates in the old version, then the
system allows the update. If you sign the version without using a matching
certificate, you will also need to assign a different package name to the
application — in this case, the user installs the new version as a
completely new application. </li>
<li>Application modularity – 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 – 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>
<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>
<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 Android Market, the
key you use to sign the application(s) must have a validity period
ending after 22 October 2033. The Market server enforces this requirement
to ensure that users can seamlessly upgrade Market applications when
new versions are available. </li>
</ul>
<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>
<h2 id="setup">Basic Setup for Signing</h2>
<p>Before you begin, you should make sure that
Keytool is available to the SDK build
tools. In most cases, you can tell the SDK build tools how to find Keytool by setting
your <code>JAVA_HOME</code> environment variable to references a suitable JDK.
Alternatively, you can add the JDK version of Keytool to your <code>PATH</code> variable.</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>If you will release your application to the public, you will also need to have
the Jarsigner tool available on your machine. Both Jarsigner and Keytool are included
in the JDK. </p>
<h2 id="debugmode">Signing in Debug Mode</h2>
<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>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>
<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> > <strong>Preferences</strong> >
<strong>Android</strong> > <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>
<h3>Eclipse Users</h3>
<p>If you are developing in Eclipse/ADT (and have set up Keytool 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 .apk 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>
<h3>Ant Users</h3>
<p>If you are using Ant to build your .apk files, 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}guide/developing/other-ide.html#DebugMode">Developing In Other IDEs: Building
in debug mode</a> for more information.</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>
<p>When the certificate expires, you will get a build error. On Ant builds, the error
looks like this:</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>
<p>In Eclipse/ADT, you will see a similar error in the Android console.</p>
<p>To fix this problem, simply delete the <code>debug.keystore</code> file.
The default storage location for AVDs is in <code>~/.android/avd</code> on OS X and Linux,
in <code>C:\Documents and Settings\<user>\.android\</code> on Windows XP, and in
<code>C:\Users\<user>\.android\</code> on Windows Vista.</p>
<p>The next time you build, the build tools will regenerate a new keystore and debug key.</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>
<h2 id="releasemode">Signing for Public Release</h2>
<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</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>
</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>
<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>
<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 Android Market, 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>
</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>
<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>-keystore <keystore-name>.keystore</code></td><td>A name
for the keystore containing the private key.</td>
</tr>
<tr>
<td><code>-storepass <password></code></td><td><p>A 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, 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>-alias <alias_name></code></td><td>An alias for the key.</td>
</tr>
<tr>
<td><code>-keyalg <alg></code></td><td>The encryption algorithm to use
when generating the key. Both DSA and RSA are supported.</td>
</tr>
<tr>
<td><code>-dname <name></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>-validity <valdays></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>-keypass <password></code></td><td><p>The password for the 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, 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 -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 —
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://java.sun.com/j2se/1.5.0/docs/tooldocs/#security">
http://java.sun.com/j2se/1.5.0/docs/tooldocs/#security</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, open
the <em>Overview</em> 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><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 build.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><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 build.properties} file,
see <a href="{@docRoot}guide/developing/other-ide.html#ReleaseMode">Developing In Other
IDEs: Building in release mode</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 <keystore-name>.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>-storepass <password></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 <password></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 -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>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://java.sun.com/j2se/1.5.0/docs/tooldocs/#security">
http://java.sun.com/j2se/1.5.0/docs/tooldocs/#security</a></p>
<h3 id="align">4. Align the final APK package</h3>
<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 .apk (the input) and the second file is the destination .apk file (the output).
If you're overriding an existing .apk, add the {@code -f} flag.</p>
<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>For more information, read about the
<a href="{@docRoot}guide/developing/tools/zipalign.html">zipalign</a> tool.
<h3 id="ExportWizard">Compile and sign with Eclipse ADT</h3>
<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>
<p>To create a signed and aligned .apk in Eclipse:</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="secure-key">Securing Your Private Key</h2>
<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>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>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>
<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>
</ul>
<p>In general, if you follow common-sense precautions when generating, using,
and storing your key, it will remain secure. </p>
|