> For the complete documentation index, see [llms.txt](https://docs.bool.network/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.bool.network/interoperability-protocol/architecture.md).

# Architecture

<figure><img src="/files/CII2CzMmQOIFouyUSMkr" alt=""><figcaption><p>General system design of Bool Network.</p></figcaption></figure>

### Underlying Technologies

Bool Network is the first permissionless cross-chain protocol based on Multi-Party Computation (MPC), Trusted Execution Environment (TEE), and Zero Knowledge Proof (ZKP) to facilitate omnichain interoperability across heterogeneous ecosystems.&#x20;

We furthermore proposed [Ring VRF](/interoperability-protocol/dynamic-hidden-committee-dhc/lifecycle.md#ring-vrf-protocol), a ZKP-based protocol to guarantee the underlying security of the system. Technical details about Ring VRF can be found in this [paper](https://ieeexplore.ieee.org/document/9903072).

### Key Components

In general, the kernel of Bool Network consists of three main modules: Dynamic Hidden Committees, BoolChain and an External Relayers System. Each of these is described below, along with their functionality in Bool Network.

#### [Dynamic Hidden Committees (DHC)](#dynamic-hidden-committees-dhc)

* Security guards in Bool Network to ensure the safety of cross-chain messages from the application layer.
* Each committee manages a unique private key which has been distributed to a specific group of MPC nodes.
* Each collection of private key fragments is separately stored in the TEE hardware of a committee's members, i.e. MPC nodes.&#x20;
* Ring Verifiable Random Function (Ring VRF) protocol is the underlying algorithm to protect and prove the committee's membership of an MPC node.

#### Bool Chain

* A public chain which performs as an ordinarily distributed ledger.
* At the early stage, the chain is specialized to support and record the lifecycles and actions of [Dynamic Hidden Committees](/interoperability-protocol/dynamic-hidden-committee-dhc.md) in the network.&#x20;
* It is an EVM-compatible blockchain where applications can be built on top of the Bool Chain in the future.

#### External Relayers

* Refer to participants who are responsible for submitting destination transactions in Bool Network.
* Designed as a competitive, efficient, and highly accessible system which is open to the market.
* Participants can profit from each transaction that they submitted to the destination chain.
* Do not guarantee the security of cross-chain messages.

### Infrastructure Layer

We deployed several primary contracts on each blockchain to help developers build their omnichain applications on Bool Network:

* `AnchorFactory`: deploy `Anchor` contracts which serve as application-specific endpoints to connect users' contracts with the core module of Bool.
* `Messenger`: an official cross-chain message delivery port which connects to all the anchor contracts on the same chain. It has two main functionalities: transmit source chain messages to Bool Network and forward messages to registered anchor contracts on the destination chain.&#x20;

{% hint style="info" %}
The above description of the infrastructure layer only fits ecosystems that have smart contracts or similar structures. The alternative design for exotic networks will be published in the future.
{% endhint %}

### Application Layer

This layer contains all the ecosystems/protocols/applications built on top of BOOLNetwork, including but not limited to tokens, NFTs, DeFis, cross-chain protocols, Oracles and public chains.