It's certainly closed source, but their E2E protocol is laid out in their white paper. You can determine if a given version of the app is conforming to the pro

It's certainly closed source, but their E2E protocol is laid out in their white paper. You can determine if a given version of the app is conforming to the protocol or not at some point in time. After a short search I was able to find this attempt: https://www.delaat.net/rp/2018-2019/p25/report.pdf https://www.delaat.net/rp/2018-2019/p25/report.pdf Which was inconclusive.