The app was developed with US government and CIA cut-out funds. It's installed by default on all CIA devices. Alongside TOR they are both CIA created honeypots. Its creation was funded by US grants for "internet freedom" from CIA-aligned cut-out organizations and NGOs. The founders, funders and administrators have ties with both the US intelligence agency as well as silicon valley. Anti-imperialist forces worldwide ban its use within their own forces due to known leaks.

https://thehill.com/policy/national-security/5213210-national-security-leaders-signal-chat/

https://cyberscoop.com/tor-signal-funding-donald-trump-steve-bannon-encryption/

^ Here's an article with a bunch of pro-government libs complaining about about Trump cutting the millions of dollars the US government (through its various "aid" organizations) to TOR and Signal.

With an annual budget of more than $700 million, the BBG is the U.S. government’s largest public-diplomacy program, reaching an audience of hundreds of millions through television, radio and websites meant to inject American-style, pro-democracy news into more closed societies. The agency’s history and the organizations it supervises — Voice of America, Radio Free Asia, Middle East Broadcast Networks and so on — extend back to World War II. It continues to be a major source of information in suppressive countries around the world.

In addition to its massive news operation, BBG is among the most important entities funding technology that allows users free and unfettered access to the internet. The initial big idea behind the funding — which had bipartisan support — was to open up countries where censorship in a problem, such as China. However, growing domestic worries over surveillance have seen growing numbers of Americans adopt the tools funded by their government.

It's US government bullshit, and it's not secure.