I've been thinking about Signal's intelligence use off and on the last couple years (as a former military intel guy). What a tool it must have been to keep running sources in Afghanistan after the collapse, for example. In the era of great power competition, plenty of proxy battlegrounds become denied terrain for spooks, and they must surely love robust mobile apps and bitcoin to interface with and pay sources. It'll be interesting to watch what OTF prioritizes if/as the threats from Russia, China, Iran, North Korea, etc. escalate. This article raised my familiarity with the various programs - thanks for sharing!