Android Signature Packaging

First, Android What's the role of signature?

1. Application Upgrade: If you want users to seamlessly upgrade to a new version, you must sign with the same certificate. This is because only the same certificate is signed and the system is allowed to install the upgraded application. If you have a different certificate, your application will be asked to take a different package name, in which case it is equivalent to installing a completely new application. If you want to upgrade the application, the signing certificate must be the same, the package name is the same!
2. Application modularity: The Android system can allow multiple applications signed by the same certificate to run in one process, and the system actually takes them as a single application, where we can deploy our application as a module, and the user can upgrade one of the modules independently.
3. Code or data sharing: Android provides a signature-based permission mechanism, so one application can expose its functionality to another application that is signed with the same certificate. By signing multiple applications with the same certificate and leveraging signature-based permission checks, you can share code and data in a secure way between applications.

Ii. Notes on Signature

1. All Android apps must have digital signatures, no applications that do not have digital signatures, including those running on the emulator. Android does not install apps without a digital certificate.
2. Signed digital certificates do not require authority to authenticate, is the developer's own production of digital certificates, known as self-signed.
3. Simulator development environment, the development of the program through the ADB interface upload will be automatically signed with the debug permission before passing to the emulator.
4. When you publish an Android app, you must use a digital certificate generated by a suitable private key to sign the program and not be published using the ADT plugin or the debug certificate generated by the Ant tool.
5. Digital certificates are valid, and Android only checks the validity of the certificate when the application is installed. If the program is already installed on the system, it does not affect the normal functionality of the program, even if the certificate expires.
6. Instead of determining which applications an end user can install, Android uses digital certificates to identify the author of an application and to establish a trust relationship between applications.

Iii. Generating signatures

1. Start menu, search cmd

2. Open cmd

3. Enter. Android

4. Use the command keytool-list-v-keystore debug.keystore

5. Need to install Keytool, the way is to install the JDK, Baidu search jdk and download the installation, specific platform according to the actual situation choice

6. After installation, go to the JDK installation bin directory and copy the address

7. Go back to cmd command window, enter CD + Space, and click Paste on the right of the title bar

8. Enter to this directory

9. Re-enter keytool-list-v-keystore debug.keystore command and enter, error occurred

10. Execute the following command first keytool-genkey-v-keystore Debug.keystore-alias androiddebugkey-keyalg rsa-validity 10000

11. Follow the prompts to enter the password (self-determined), the secret to protect the answer, etc. to later need to re-enter the password, build completed

12. To the Keytool directory, see Debug.keystore has been generated successfully

Iv. How to sign Genexus when developing Android apps

During the development process, Genexus has brought its own Debug.keystore signature files to enable developers to develop quickly.

However, if development is complete, it is recommended that you use your own signature files when you are in the production environment.

In the corresponding attribute, as shown in, specify to the KeyStore file that you have generated (you can refer to the previous content of this article), configure the corresponding name/store password/Key password and other information,

Recompile so that Genexus will use the configured signature file when generating a new apk file.

Android Signature Packaging