David A. Wheeler's Page on Countering 'Trusting Trust' through Diverse Double-Compiling (DDC) - Countering Trojan Horse attacks on Compilers| dwheeler.com
As of our latest Android release, Signal builds are reproducible. Reproducible builds help to verify that the source code in our GitHub repository is the exact source code used to build the compiled Signal APK being distributed through Google Play.| Signal Messenger