What about WhatsApp, Telegram? I don't use them, but saying that there are no options today for secure, encrypted communication raises my eyebrow.
WhatsApp at least has end to end encryption- though that alone isn't enough, but it is not open source and is owned by Facebook. By default, it shares your number and your contacts' numbers with Facebook.
Neither Telegram nor WhatsApp are viable alternatives to anyone interested in privacy.
Why? I'm not trying to nitpick, I just don't know much on the subject. Not being open source doesn't really concern me nor the fact that my number is known by Facebook. My telecom company knows it, my mother knows it and all my friends know it + also all the companies know it who are used by my friends.
Are you suggesting that the application under discussion here is a viable alternative? If so, how?
https://core.telegram.org/mtproto https://telegram.org/apps#source-code