Better Terminal Emulator Pro - Harness the native Linux command-line potential of Android with this Terminal.
Microsoft BitLocker - BitLocker is a full disk encryption feature included with Windows Vista and later.
Termux - Terminal emulator and Linux environment for Android
Paubox - Paubox provides HIPAA compliant email encryption without the hassle of extra steps.
Tabby.sh - Tabby is a free and open source SSH, local and Telnet terminal with everything you'll ever need.
OpenSSH - OpenSSH is a free version of the SSH connectivity tools that technical users rely on.