- they’re open source and people like me regularly read parts of their code and in some cases use their code elsewhere. Also several undergraduates and PhD’s have written research papers on the signal protocol. It’s also the subject of a lot of security research (there was a good talk at defcon this year that found some minor privacy issues with signal notifications)
- no one has built a decentralized e2ee messaging app that’s actually secure and has privacy anything like the bar Signal sets. Matrix are getting close, they’ve recently made some encouraging changes, but it will take some time to verify.
- Moxie the founder of Signal gave a talk about the challenges of building something like signal in a decentralized environment - https://youtu.be/1W5fuqySBnE
- Signal is a nonprofit. They have stated repeatedly they will shutdown the app in regions or countries that make backdoors required by law.
* Do you know of anything better?
* Do you not trust the Signal Organisation? They've aren't able to subvert their encryption on the servers, and have publicly stated that they will leave a region before integrating client-side scanning. I for one believe them, since it's their raison d'être.