What are some alternatives?
When comparing Keybase for Mobile and Send, you can also consider the following products
Signal - Fast, simple & secure messaging. Privacy that fits in your pocket.
MagicPad - Free, simple, and private, offline text encryption suite.
MyChat - Secure instant messenger for any network
Clips by Fly Labs - The simplest mobile video editor in the world
Tox - Send messages, files, create groups and make Tox to Tox audio and video calls. Securely.
Life Lapse App - A free time lapse app for your life