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android / platform / tools / apksig / refs/heads/android11-dev
commit79142cc90af1ccae85318cff844393113d261096[log] [tgz]
authorMichael Groover <mpgroover@google.com>Thu Jul 16 20:17:24 2020 -0700
committerMichael Groover <mpgroover@google.com>Thu Jul 16 20:29:38 2020 -0700
tree0a8a3e5e28788779d8d260c4835659e1d2c8750b
parentd07c3bde5513af873f2e675a6be8d3ac073d5263 [diff]
Add conscrypt provider to apksigner to support PSS

The platform supports APKs signed with a PSS signature algorithm, but
the default providers used by apksigner do not include this support.
This commit adds the conscrypt provider to apksigner to allow
verification of APKs signed with a PSS signature algorithm. Note the
changes to the apksigner script only support including the native
conscrypt library as part of the Android tree; additional work is
required to include the native library in an sdk build-tools release.

Bug: 161323964
Test: gradlew test
Test: Manually verified an APK signed with a PSS signature algorithm
Change-Id: I0ba7e93cc8792760590c3a98eb87127d0df71ce3
3 files changed
tree: 0a8a3e5e28788779d8d260c4835659e1d2c8750b
  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.