Reproducible Android Builds
Article Summary
Signal just made their Android builds reproducible, and they're practically begging you not to send them panicked encrypted emails about it. This is transparency done right.
Signal's Android team shipped reproducible builds as a weekend hack, allowing anyone to verify that the APK distributed through Google Play matches the exact source code in their GitHub repository. They've published a Docker image that makes verification straightforward for developers.
Key Takeaways
- Docker-based verification process compares Play Store APK to GitHub source code
- Simple apkdiff script confirms compiled APK matches published source exactly
- Native libraries (WebRTC) remain non-reproducible due to legacy Gradle NDK limitations
- Team emphasizes this wasn't driven by legal pressure, just good engineering practice
Critical Insight
Signal now lets anyone verify their Android APK matches public source code through a simple Docker-based build process.
