Install signapk by entering the following commands in the terminal:
sudo apt update sudo apt install signapk
Description:
Command line tool for signing Android ZIP/JAR/APK
signapk is a command line tool for signing ZIP files, including JARs, APKs, and Over-The-Air (OTA) updates, in a way compatible with Android's mincrypt verifier, using EC or RSA keys and SHA1 or SHA-256. The tool can additionally sign APKs using APK Signature Scheme v2. It is the standard tool used to sign APK and JAR files distributed as part of Android ROMs.
Homepage: https://android.googlesource.com/platform/build
Version: 1:7.0.0+r33-1
Section: universe/devel