TextoCrypt

You know how to send a text message (or SMS) with your standard application? If yes, then you know how to use TextoCrypt.
TextoCrypt has been designed to send and receive encrypted text messages simply and almost transparently for the user.
The only prerequisite is to exchange your certificate with the ones of your correspondents. Then, you can send and receive text messages as usual.
TextoCrypt generates a certificate containing a public key during installation. Once this certificate has been sent to all relevant recipients, key management is fully transparent. Encryption keys are renewed every 24 hours. Text messages are stored encrypted on the smartphone.
TextoCrypt uses the AES in CBC mode for encryption, ECIES for key management and elliptic curve "255-19" for public/private key pairs.
No data (private or contact) is stored on-line.
TextoCrypt is not the default text messaging app and users can keep their standard text messaging app and use it whenever they want. Encrypted text messages sent and received with TextoCrypt will appear "scrambled" in the standard app.