# Architecture

## Overview

MAP Protocol is a peer-to-peer cross-chain infrastructure that enables secure and decentralized interoperability between heterogeneous blockchains. The architecture is designed with a three-layer structure.

## Three-Layer Architecture

```
┌─────────────────────────────────────────────────────────────────────────┐
│                        Application Layer                                 │
│                                                                          │
│    Omnichain DApps    │    Cross-chain Bridges    │    Other Apps       │
└─────────────────────────────────────────────────────────────────────────┘
                                    │
                                    ▼
┌─────────────────────────────────────────────────────────────────────────┐
│                     MOS (MAP Omnichain Service) Layer                    │
│                                                                          │
│    Message Passing    │    Asset Transfer    │    Data Verification     │
└─────────────────────────────────────────────────────────────────────────┘
                                    │
                                    ▼
┌─────────────────────────────────────────────────────────────────────────┐
│                         Protocol Layer                                   │
│                                                                          │
│    MAP Relay Chain    │    Light Clients    │    TSS Network            │
└─────────────────────────────────────────────────────────────────────────┘
```

### Layer 1: Protocol Layer

The foundation layer providing core cross-chain verification and consensus.

**Components:**

| Component       | Description                                          |
| --------------- | ---------------------------------------------------- |
| MAP Relay Chain | EVM-compatible blockchain serving as the relay hub   |
| Light Clients   | On-chain verification of other chain's state         |
| TSS Network     | Threshold signature scheme for decentralized custody |
| Maintainers     | Network participants maintaining cross-chain state   |

### Layer 2: MOS (MAP Omnichain Service) Layer

The service layer providing cross-chain messaging and asset transfer capabilities.

**Components:**

| Component        | Description                              |
| ---------------- | ---------------------------------------- |
| Message Protocol | Standard for cross-chain message format  |
| Messenger        | Off-chain service relaying messages      |
| Vault/Gateway    | Asset custody and verification contracts |

### Layer 3: Application Layer

The user-facing layer where omnichain applications are built.

**Examples:**

* Cross-chain DEX
* Omnichain NFT
* Cross-chain Lending
* Multi-chain Governance

## MAP Relay Chain

MAP Relay Chain (Atlas) is the core of MAP Protocol, serving as:

1. **Relay Hub**: Central point for cross-chain message routing
2. **Verification Center**: Hosts light clients for connected chains
3. **Governance Platform**: Manages validators, maintainers, and protocol parameters

### Consensus

* **Consensus Algorithm**: Istanbul BFT (IBFT)
* **Block Time**: \~5 seconds
* **Finality**: Instant finality with 2/3+ validator agreement
* **Staking**: Proof of Stake with MAPO token

### Key Features

* EVM compatible
* Precompile contracts for cryptographic operations
* Genesis contracts for staking and governance

## Cross-Chain Verification

MAP Protocol supports two verification methods:

### Light Client Verification (v1)

```
Source Chain              Relay Chain              Target Chain
     │                         │                        │
     │    Block Header         │                        │
     ├────────────────────────►│                        │
     │                         │                        │
     │    Merkle Proof         │    Verified Message    │
     ├────────────────────────►├───────────────────────►│
     │                         │                        │
```

### TSS Verification (v2)

```
Source Chain              Maintainer Network         Target Chain
     │                         │                        │
     │    Cross-chain Event    │                        │
     ├────────────────────────►│                        │
     │                         │                        │
     │                    TSS KeySign                   │
     │                         │                        │
     │                         │    TSS Signature       │
     │                         ├───────────────────────►│
     │                         │                        │
```

## Network Participants

### Validators

* Produce blocks on MAP Relay Chain
* Participate in IBFT consensus
* Stake MAPO tokens
* Can register as Maintainers

### Maintainers

* **v1**: Update light client state
* **v2**: Participate in TSS signing, observe cross-chain events

### Messengers

* Relay cross-chain messages
* Submit proofs to target chains
* Earn fees for message delivery

### Relayers (v2)

* Submit TSS signatures to target chains
* Can be Maintainers or independent operators

### LP Providers (v2)

* Provide liquidity to Vaults
* Earn cross-chain fees

## Supported Chains

MAP Protocol is designed to support:

* **EVM Chains**: Ethereum, BSC, Polygon, Arbitrum, etc.
* **Non-EVM Chains**: Near, Solana, TON
* **Bitcoin**: Via TSS-based Vault

## Security Model

### Decentralization

* No single point of failure
* Distributed validation and signing
* On-chain governance

### Cryptographic Security

* Light client verification based on source chain consensus
* TSS threshold signature (2/3 fault tolerance)
* Slashing for malicious behavior

### Economic Security

* Staking requirements for validators and maintainers
* Slashing penalties for misbehavior
* Incentive alignment through rewards