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android / platform / tools / apksig / 6c01b3d573894f3da948cd4d5e48b694831b9c56
commit6c01b3d573894f3da948cd4d5e48b694831b9c56[log] [tgz]
authorDan Cashman <dcashman@google.com>Fri Mar 30 19:22:38 2018 -0700
committerDaniel Cashman <dcashman@google.com>Fri Apr 06 13:35:37 2018 +0000
treeb2e1147db251ade37046ea6a48a29c394e4ca4ca
parent6b48791c8043284fd59e83f033f677cece497481 [diff]
Add ROLLBACK past signing cert capability.

Add a new capability that may be granted to past signing certificates
after changing to a new signing certificate that will allow applications
to go back to a previous signing certificate.  This capability is
intended to not be granted, but may be added later in the event that
a signing certificate change caused undesirable behavior.

(cherry-pick of commit: 26f734ffa011f6f22e5f83a9a80b877ddcc0c10a)
Bug: 73927694
Test: bazel test ...
Change-Id: Ic837ec66a97865ce941b202093e9bbe26fcfba90
Merged-In: Ic837ec66a97865ce941b202093e9bbe26fcfba90
1 file changed
tree: b2e1147db251ade37046ea6a48a29c394e4ca4ca
  1. etc/
  2. src/
  3. Android.bp
  4. android_plugin_for_gradle.gradle
  5. apksig.iml
  6. BUILD
  7. build.gradle
  8. LICENSE
  9. OWNERS
  10. 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.