Source (required if based on other people's work): https://github.com/evpo/EncryptPad/releases/tag/v0.4.0.2
EncryptPad is an application for viewing and editing symmetrically encrypted text. Using a simple and convenient graphical and command line interface, EncryptPad provides a tool for encrypting and decrypting binary files on disk while offering effective measures for protecting information, and it uses the most widely chosen quality file format OpenPGP RFC 4880. Unlike other OpenPGP software which main purpose is asymmetric encryption, the primary focus of EncryptPad is symmetric encryption.
NOTE: This is only to provide appimages, I am not the developer.