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android / platform / tools / apksig / 8112df60ad8f079b019fd37f57010b9ab6ca02bc
commit8112df60ad8f079b019fd37f57010b9ab6ca02bc[log] [tgz]
authorXin Li <delphij@google.com>Mon Aug 14 15:45:09 2023 -0700
committerXin Li <delphij@google.com>Mon Aug 14 15:45:09 2023 -0700
tree42d89bdbdde8814cfb0102c0d3fbb31e10cb1e45
parent37782e7003a4ad5d6a85abc49e953f3c02a60cee [diff]
parent9dda3541de197f6b085d1a81c0dcb08378c5e650 [diff]
Merge Android U (ab/10368041)

Bug: 291102124
Merged-In: I2c1e0cfe06387de812d3c7f86a4ad47323ec9972
Change-Id: Ib0a0d1b4dd61ad5d589f73a8cc9769578d4224e5
tree: 42d89bdbdde8814cfb0102c0d3fbb31e10cb1e45
  1. etc/
  2. src/
  3. Android.bp
  4. android_plugin_for_gradle.gradle
  5. build.gradle
  6. LICENSE
  7. OWNERS
  8. README.md
README.md

apksig

apksig is a project which aims to simplify APK signing and checking whether APK signatures are expected to 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). apksig is meant to be used outside of Android devices.

The key feature of apksig is that it knows about differences in APK signature verification logic between different versions of the Android platform. apksig thus thoroughly checks whether an APK's signature is expected to verify on all Android platform versions supported by the APK. When signing an APK, apksig chooses 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

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.
  • 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.
  • (Default)ApkSignerEngine which abstracts away signing APKs from parsing and building APKs. 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 because these classes may change any time without regard to existing clients outside of apksig and apksigner.

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.