What is a one time pad? A one time pad is a theoretically perfect, secure method of sending a message, they are essentially one use keys used to send secure text messages. The app allows users to exchange secure, one time pads via NFC and then communicate securely over the Internet. One time pads must be exchanged in person. Once they are exchanged you can send theoretically unbreakable messages over the Internet. The one time pad was frequently used by the KGB to transmit sensitive information. Eulen is simply a modern implementation of the one time pad with a complete messaging system to transfer the messages so you don't have to copy / paste data into emails.
You can also use Eulen to encrypt photos with strong AES encryption. This allows two users to exchange photos that only the other user can see.
More information about one time pads: https://en.wikipedia.org/wiki/One-time_pad
GitHub project: https://github.com/gtom1984/Eulen