I don't think either should be trusted. The initial funding for signal was from the US intelligence agencies, not just "the US government". I don't trust the FBI/CIA to fund a messaging app that doesn't allow them some backdoor to spy on messages. Tucker Carlson also claimed the government found out about his plans to interview Putin because they could read his signal messages (I have no idea if these claims have merit, but it's concerning).
If they had some other way into his phone they wouldn't need to break signal at all (not that it rules it out either ofc).
0-days for the latest android/ios devices are well within the reach of three letter agencies
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