The Confidential Blockchain Protocol

How the Bubble network fits together: the Solidity library, host contracts, the connector, the MPC engine, and the Bubble interactor.

The Bubble network consists of several interconnected entities that collaborate to enable secure multi-party computation (MPC) over encrypted data while maintaining on-chain verifiability.

Below is a conceptual overview of the structure and the connections between the entities.

GC Solidity library: Enables developers to write confidential smart contracts in plain Solidity using encrypted data types and operations.
Host contracts: Trusted on-chain contracts deployed on EVM-compatible blockchains. They manage access control and trigger off-chain encrypted computation.
Bubble: Services that validates encrypted inputs, manages access control lists (ACLs), calls the MPC engine to run GC computations, saves data in the database and return decrypt results to the requested contracts.
MPC engine: A MPC network that computes the Garbled circuit protocol.
Bubble interactor: An off-chain service that gets user requests, such as onboard user to the system and encrypt data to a specific user using his secret key.