I have used Threema and I like it, but the barrier is that it is not a free app. I've only been able to get fellow nerds to install it.
I like the idea that it indicates the level of safety you have with another person quite clearly. The highest level is when you physically scan one another's QR codes when you meet in person so you know nobody is inserting themselves into your key exchange.
I like the idea that it indicates the level of safety you have with another person quite clearly. The highest level is when you physically scan one another's QR codes when you meet in person so you know nobody is inserting themselves into your key exchange.