This app uses asymmetric encryption to encrypt messages. The app starts by creating user's public key and private key.

If the user wants to send a message to another user, the app asks for the other user's public key on the server.

The app then encrypts the message with the public key of the target user and send it to the target user. The target user can then use his private key to decrypt the message.

The user can also encrypt a message with a password of certain length. The target user needs to know the password to read the message.

This app stores the user's private key in the device. It won't store the private key on the server, in order to protect the user. So, if the user uses a new device, the app will generate new private key and public key. The old messages that encrypted with the old public key of the user, won't be able to be decrypted on the new device. The user needs to use the old device to decrypt the old messages.

The app is intended to be used by the user as a way to send infrequent, encrypted messages. In the other words, it is not intended to be used as a normal chat app.