YouTube App Reverse Engineering Suite

YT-RE provides several facilities aiding the YouTube Android app reverse engineering process. These include our own set of deobfuscation mappings, tracking of obfuscated artifacts across releases, integration with several well-known reverse engineering tools and a local Git repository generator.

Getting Started

1. Clone the repo.
2. Download the correct version (see current branch name) of the YouTube APK, preferably from APKMirror (nodpi is the default).
3. Place the APK at the root of this directory and rename it to youtube-<version>.apk (replace <version> with the adequate version string).
4. Run ./gradlew enigma or /gradlew jadx to use and/or edit the mappings (see the tasks' descriptions below).
5. If you want to, commit and push your work to a fork and open a PR with your changes. Please have a look at the naming conventions before submitting one.

Gradle Tasks

YT-RE uses Gradle to provide a number of utility tasks for working with the mappings. Please note, to run our build script Java 17 is required!

enigma

Download, setup and launch the latest version of Enigma automatically configured to use the converted jar and mappings.

Compared to launching Enigma externally, the gradle task adds a name guesser plugin that automatically maps enums and a few constant field names.

jadx

Download, setup and launch the latest version of JADX automatically configured to use the provided APK and mappings.

Please do not enable JADX's built-in auto-deobfuscation, as this feature can mess with exported package names.

buildTinyMappingFiles

Build Tiny and Tiny v2 mapping files between official (obfuscated) names and our renames ("named").

buildNamedJar

Builds a deobfuscated jar with deobfuscation mappings applied (youtube-<yt-version>-named.jar).

Tasks for updating to a new YT version

These are of no use to the average user, but are listed here anyway for completeness' sake. To update the project to a new YT version, repeat steps 2 and 3 from Getting Started, but this time with the YT version you want to update to. Then run the following tasks. Note that they all require passing an additional newYtVersion property via -PnewYtVersion='<new-version>'.

matcher

Run Matcher with the provided youtube-<current-version>.apk and youtube-<new-version>.apk as inputs, so you can update the mappings to a newer YT version.

As soon as Matcher is started and has analyzed its input files, select Matching → Auto match all. Depending on your Computer's hardware, this may take several hours. A modern multi-core CPU with at least 6 cores and 16 GB of RAM are recommended! Matcher itself requires at least 6 GB of memory. After the process has finished, take care of the remaining red entries. You may have to double-check each class and method if any containing children are still unmatched. If you can't find a similar enough counterpart, perhaps the class/method/etc. has been removed from the newer APK. In this case, click the "unmatchable" button in the bottom pane.

Once you're confident with your results, go to File → Save matches and save the file into the matches folder. Please name it <current-version> - <new-version>.match; see the already existent match files.

To update the mappings, go to to File → Save mappings (Enigma), select the mappings folder, give permission to overwrite the existing data and use the following configuration to export the updated files:

jadxNewYtVersion

Opens the new YouTube version's APK in JADX. This task should only be used for assisting in the matching process, don't import or export any mappings from there.

updateIntermediary

Generates a new Tiny file with updated intermediaries into the ./intermediary directory.