Gotham-engine

Gotham engine is the engine for gotham-city server. It abstracts through traits, routes for keygen and sign in a 2P setting for Lindell17 protocol. The level of abstraction allows the implementers to pass specific DB api and authorization policies. The engine provides default trait implementations for keygen and sign logic, such that the implementers are only implementing the peripherals. Any potential change at the cryptographic protocol is done through the gotham-engine and and changes are reflected automatically at the implementers through default implementations. An example of usage is provided in the gotham-city project.

Example Workflow for an Implementer:

1. Instantiate empty traits for KeyGen and Sign:

   pub struct PublicGotham {
      rocksdb_client: rocksdb::DB,
   }
   impl KeyGen for PublicGotham {}
   impl Sign for PublicGotham {}

2. Implement the Db trait

   impl Db for PublicGotham {
    async fn insert(
        &self,
        key: &DbIndex,
        table_name: &dyn MPCStruct,
        value: &dyn Value,
    ) -> Result<(), DatabaseError> {
        ///implementation
    }

    async fn get(
        &self,
        key: &DbIndex,
        table_name: &dyn MPCStruct,
    ) -> Result<Option<Box<dyn Value>>, DatabaseError> {
           ///implementation
   }

3. Implement the TxAuthorization trait

impl Txauthorization for Authorizer {
    /// the granted function implements the logic of tx authorization. If no tx authorization is needed the function returns always true
    fn granted(&self) -> Result<bool, DatabaseError> {
           ///implementation
    }
}

4. Spin a rocket server and mount gotham-engine existing endpoints for keygen and sign

rocket::Rocket::build()
        .register("/", catchers![internal_error, not_found, bad_request])
        .mount(
            "/",
            routes![
                gotham_engine::routes::wrap_keygen_first,
                gotham_engine::routes::wrap_keygen_second,
                gotham_engine::routes::wrap_keygen_third,
                gotham_engine::routes::wrap_keygen_fourth,
                gotham_engine::routes::wrap_chain_code_first_message,
                gotham_engine::routes::wrap_chain_code_second_message,
                gotham_engine::routes::wrap_sign_first,
                gotham_engine::routes::wrap_sign_second,
            ],
        )

5. Pass to the gotham-engine the State for Db and TxAuthorization trait as dyn trait objects

   .manage(Mutex::new(Box::new(x) as Box<dyn gotham_engine::traits::Db>))
   .manage(Mutex::new(
            Box::new(tx) as Box<dyn gotham_engine::traits::Txauthorization>
        ))
   

   Details

   Documentation