What are some alternatives?
When comparing MagicPad and Keybase for Mobile, you can also consider the following products
MyChat - Secure instant messenger for any network
Signal - Fast, simple & secure messaging. Privacy that fits in your pocket.
Send - Instant messaging meets email (by Microsoft)
Tox - Send messages, files, create groups and make Tox to Tox audio and video calls. Securely.
Brosix Instant Messenger - Secure instant messenger for your team
Threema - A secure, end-to-end encrypted Swiss instant messenger with a focus on privacy.