Bug#847657: ITP: apksig -- sign and verify Android APK signatures

[Hans-Christoph Steiner <hans@eds.org>]

Package: wnpp
Severity: wishlist
Owner: "Hans-Christoph Steiner" <hans@eds.org>

* Package name    : apksig
  Version         : 0.3
  Upstream Author : The Android Open Source Project
* URL             : https://android.googlesource.com/platform/tools/apksig
* License         : Apache-2.0
  Programming Lang: Java
  Package source  :
https://anonscm.debian.org/git/android-tools/android-platform-tools-apksig.git
  Description: sign and verify Android APK signatures

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.

The project consists of two subprojects:

    apksig -- a pure Java library, and
    apksigner -- a pure Java command-line tool based on the apksig library.


apksig library offers three primitives:

    ApkSigner which signs the provided APK so that it verifies on all
Android platform versions supported by the APK. The range of platform
versions can be customized if necessary.
    ApkVerifier which checks whether the provided APK is expected to
verify on all Android platform versions supported by the APK. The range
of platform versions can be customized if necessary.
    (Default)ApkSignerEngine which abstracts away signing an APK from
parsing and building an APK file. This is useful in optimized APK
building pipelines, such as in Android Plugin for Gradle, which need to
perform signing while building an APK, instead of after. For simpler use
cases where the APK to be signed is available upfront, the ApkSigner
above is easier to use.

NOTE: Some public classes of the library are in packages having the word
“internal” in their name. These are not public API of the library. Do
not use *.internal.* classes directly.
apksigner command-line tool

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.