How to Enable Google Play App Signing

I think a lot of developers are trying to learn more about the new Google Play App Signing feature presented at Google I/O 2017.

The ability to store the keystore to sign the apps inside Google Play save you the effort to safely store the keystore and can help the system to optimize the APKs served to every device, based on hardware and OS characteristics.

You can read more about this topic in the official documentation here : https://developer.android.com/studio/publish/app-signing.html#google-play-app-signing.
With the following answer, i will explain a bit better the steps you need to follow to upload your original keystore and how to create the new upload keystore, which you will need to sign your APK from this point onwards.

This guide is oriented to developers who already have an application in the Play Store. If you are starting with a new app the process it's much easier and you can follow the guidelines of paragraph "New apps" from here
Prerequisites that 99% of developers already have :

1. Android Studio
2. JDK 8 and after installation you need to setup an environment variable in your user space to simplify terminal commands. In Windows x64 you need to add this : C:\Program Files\Java\{JDK_VERSION}\bin to the Path environment variable. (If you don't know how to do this you can read my guide to add a folder to the Windows 10 Path environment variable).

Step 0: Open Google Play developer console, then go to Release Management -> App Signing.

Accept the App Signing TOS.

Step 1: Download PEPK Tool clicking the button identical to the image below

Step 2: Open a terminal and type:

java -jar PATH_TO_PEPK --keystore=PATH_TO_KEYSTORE --alias=ALIAS_YOU_USE_TO_SIGN_APK --output=PATH_TO_OUTPUT_FILE --encryptionkey=GOOGLE_ENCRYPTION_KEY

Legend:

• PATH_TO_PEPK = Path to the pepk.jar you downloaded in Step 1, could be something like C:\Users\YourName\Downloads\pepk.jar for Windows users.
• PATH_TO_KEYSTORE = Path to keystore which you use to sign your release APK. Could be a file of type *.keystore or *.jks or without extension. Something like C:\Android\mykeystore or C:\Android\mykeystore.keystore etc...
• ALIAS_YOU_USE_TO_SIGN_APK = The name of the alias you use to sign the release APK.
• PATH_TO_OUTPUT_FILE = The path of the output file with .pem extension, something like C:\Android\private_key.pem
• GOOGLE_ENCRYPTION_KEY = This encryption key should be always the same. You can find it in the App Signing page, copy and paste it. Should be in this form: eb10fe8f7c7c9df715022017b00c6471f8ba8170b13049a11e6c09ffe3056a104a3bbe4ac5a955f4ba4fe93fc8cef27558a3eb9d2a529a2092761fb833b656cd48b9de6a

Example:

java -jar "C:\Users\YourName\Downloads\pepk.jar" --keystore="C:\Android\mykeystore" --alias=myalias --output="C:\Android\private_key.pem" --encryptionkey=eb10fe8f7c7c9df715022017b00c6471f8ba8170b13049a11e6c09ffe3056a104a3bbe4ac5a955f4ba4fe93fc8cef27558a3eb9d2a529a2092761fb833b656cd48b9de6a

Press Enter and you will need to provide in order:

1. The keystore password
2. The alias password

If everything has gone OK, you now will have a file in PATH_TO_OUTPUT_FILE folder called private_key.pem.
Step 3: Upload the private_key.pem file clicking the button identical to the image below

Step 4: Create a new keystore file using Android Studio.

YOU WILL NEED THIS KEYSTORE IN THE FUTURE TO SIGN THE NEXT RELEASES OF YOUR APP, DON'T FORGET THE PASSWORDS

Open one of your Android projects (choose one at random). Go to Build -> Generate Signed APK and press Create new.

Now you should fill the required fields.

Key store path represent the new keystore you will create, choose a folder and a name using the 3 dots icon on the right, i choosed C:\Android\upload_key.jks (.jks extension will be added automatically)
NOTE: I used upload as the new alias name but if you previously used the same keystore with different aliases to sign different apps, you should choose the same aliases name you had previously in the original keystore.

Press OK when finished, and now you will have a new upload_key.jks keystore. You can close Android Studio now.
Step 5: We need to extract the upload certificate from the newly created upload_key.jks keystore. Open a terminal and type:

keytool -export -rfc -keystore UPLOAD_KEYSTORE_PATH -alias UPLOAD_KEYSTORE_ALIAS -file PATH_TO_OUTPUT_FILE

Legend:

• UPLOAD_KEYSTORE_PATH = The path of the upload keystore you just created. In this case was C:\Android\upload_key.jks.
• UPLOAD_KEYSTORE_ALIAS = The new alias associated with the upload keystore. In this case was upload.
• PATH_TO_OUTPUT_FILE = The path to the output file with .pem extension. Something like C:\Android\upload_key_public_certificate.pem.

Example:

keytool -export -rfc -keystore "C:\Android\upload_key.jks" -alias upload -file "C:\Android\upload_key_public_certificate.pem"

Press Enter and you will need to provide the keystore password.
Now if everythig has gone OK, you will have a file in the folder PATH_TO_OUTPUT_FILE called upload_key_public_certificate.pem.
Step 6: Upload the upload_key_public_certificate.pem file clicking the button identical to the image below

Step 7: Click ENROLL button at the end of the App Signing page.

Now every new release APK must be signed with the upload_key.jks keystore and aliases created in Step 4, prior to be uploaded in the Google Play Developer console.
More Resources:

• Google documentation on Google Play App Signing
• Form to request the reset of your upload keystore if you lose it

Q&A

Q: When i upload the APK signed with the new upload_key keystore, Google Play show an error like : You uploaded an unsigned APK. You need to create a signed APK.
A: Check to sign the APK with both signatures (V1 and V2) while building the release APK. Read here for more details.

Source: https://stackoverflow.com/questions/44103024/how-to-enable-google-play-app-signing

Labels: Android Developer

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