Whats App But Better

Needed Keys:

• 1 Asymmetric key pair: for passing symmetric chat keys. We keep the private key, public key is posted with our user when we create our account.
• n number of symmetric keys: for when we create a chat and have to assign a symmetric key to it.

Storage:

• Our private key (from above).
• Symmetric keys for all chats.
• Data (messages, chat metadata, etc)

Need to be able to encrypt all our keys (sym and asym) with a password and send it up to our server for 'backup' so we can pull it down later and restore keys to a new device.

Whenever we restore to a new device, we'll generate a new asym public/private pair and then update our public key on the server for other people to use. Our symmetric keys we receive from others for chats needs to be stored in secure storage.