3. Encrypted messenger chat

P.2 extension: Create an encrypted messenger on BITE Chain.

When a new session is created (e.g. between Alice and Bob), a session public key and secret key are generated. Alice and Bob both gain access to the session secret key by re-encrypting it with their public keys. Messages are encrypted using the session public key. Off-chain, Alice and Bob can decrypt messages in their chat using the session secret key.