coffer/Design.org

• Communication
  • Frame
  • Message Types
• Coffer
• Coffer Server

Communication

Frame

Header ::: content-length: u64 | message-type: u8 ::: 72 bit, fixed Body ::: content: [u8; content-length] ::: conent-length byte, variable

Numbers are in network byte order.

Message Types

Ordinal	Type	Body Format	Direction	Transitions	Description
0	Hello	Public Key	C -> S	Waiting for Link	Initiates communication
1	Link	<empty>	S -> C	Put, Get	Link established, communication can start
2	Put	Coffer (sealed)	C -> S	OkPut	Merge a Coffer for the client
3	Get	Coffer (sealed)	C -> S	OkGet	Retrieve a Coffer for the client
4	OkPut	<empty>	S -> C	Put, Get	Coffer was successfully merged
5	OkGet	Coffer (sealed)	S -> C	Put, Get	Return a sealed Coffer for a Get request
63	Bye		C -> S		Close connection
127	Error		S -> C		Generic server error

• Error can be returned at any stage
• Communication can end at any stage. Communication ends when connection is closed by either side.
• Seal is determined by communication direction: C -> S: sealed by server public key, client private key S -> C: sealed by client public key, server private key

Coffer

• Multitree with each leave terminating in a Vec<u8>
• Nodes (except leaves = key path) are utf8 strings
• A Put request must contain a fully determined Coffer (all leaves are values)

• A Get request contains a partially determined Coffer (values are ignored)

  • If a node resolves to a parent, the subtree (which is also a Coffer) is returned
  • If a node resolves to a leave, the partial Coffer terminating in the leave and its value are returned

Coffer Server

A coffer-server can support multiple clients by means of sharding the keyspace. Clients are uniquely identified by their public key.

• A client can only access its shard identified by its public key
• All server responses are sealed by the client's public key and server's private key. No secrets can be extracted or communication data collected except the private keys are compromised.
• All server requests are sealed by the server's public and client's private key. No tampered requests can be sent or communication data collected except the private keys are compromised.