Module protocol 

This adds end-to-end encryption for peer communications over the base sbd communication protocol via libsodium secretstream.

Message Type Header

Adds a single-byte header to messages sent.

Messages with bytes other than the following three should be ignored for future compatibility.

• 0x10 - NewStream – must be followed by 24 byte secret stream header.
• 0x11 - Message – encrypted message including abytes.
• 0x12 - RequestNewStream – only this single byte.

Message Type Handling

• When sending a message to a new (or not recent) peer, clients MUST establish a new outgoing (encryption) secret stream state and send the 24 byte header in a “NewStream” message.
• On receiving a “RequestNewStream” message, clients MUST establish a new outgoing (encryption) secret stream state and send the 24 byte header in a “NewStream” message.
• On receiving a “NewStream” message, clients MUST establish a new incoming (decryption) secret stream state.
• On receiving a “Message” that cannot be decrypted, clients MUST (1) ignore the message, (2) delete any incoming (decryption) state, and (3) send a “RequestNewStream” message. Any message receipt tracking or re-requesting will not be handled by this library, but may be added by implementors as a layer on top of this.

Enums

Protocol

E2e crypto protocol enum.

Constants

T_MESSAGE

Encrypted stream message.

T_NEW_STREAM

Start a new stream.

T_REQ_NEW_STREAM

Request start of new stream.