Install apksigner by entering the following commands in the terminal:
sudo apt update sudo apt install apksigner
command line tool to sign and verify Android APKs
apksig is a project which aims to simplify APK signing and checking whether APK's signatures should verify on Android. apksig supports JAR signing (used by Android since day one) and APK Signature Scheme v2 (supported since Android Nougat, API Level 24). . The key feature of apksig is that it knows about differences in APK signature verification logic between different versions of the Android platform. apksig can thus check whether a signed APK is expected to verify on all Android platform versions supported by the APK. When signing an APK, apksig will choose the most appropriate cryptographic algorithms based on the Android platform versions supported by the APK being signed. . apksigner command-line tool offers two operations: . * sign the provided APK so that it verifies on all Android platforms supported by the APK. Run apksigner sign for usage information. . * check whether the provided APK's signatures are expected to verify on all Android platforms supported by the APK. Run apksigner verify for usage information. . The tool determines the range of Android platform versions (API Levels) supported by the APK by inspecting the APK's AndroidManifest.xml. This behavior can be overridden by specifying the range of platform versions on the command-line.