cmta

name	cmta
description	main concept behind cmta

CMTAT (CMTA Token) is a security token framework for tokenizing real-world financial assets on EVM-compatible blockchains. It's developed by the Capital Markets and Technology Association (CMTA).

Version: 3.2.0-rc0 | License: MPL-2.0 | Solidity: 0.8.33

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Directory Structure

contracts/
├── modules/                  # Core smart contract logic
│   ├── internal/            # Internal implementations
│   └── wrapper/             # Public-facing modules
│       ├── core/            # ERC20, Pause, Enforcement, Validation
│       ├── extensions/      # Documents, Snapshots
│       ├── options/         # Debt, ERC2771, Cross-chain
│       └── security/        # Access control
├── deployment/              # Pre-composed contract variants
├── interfaces/              # ERC standards & custom interfaces
└── mocks/                   # Test helpers
test/                        # 3,078 tests (~99% coverage)
doc/                         # Specs & audit reports

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Key Modules

Category	Modules	Purpose
Core	ERC20Base, Mint, Burn, Pause, Enforcement, Validation	Basic token operations
Extensions	Snapshot, Document, ExtraInformation	Dividends, legal docs, metadata
Options	Debt, ERC2771, ERC1363, CrossChain, Allowlist, ERC7551	Bonds, gasless tx, multi-chain, KYC
Security	AccessControl	RBAC with roles (MINTER, BURNER, PAUSER, ENFORCER)

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Deployment Variants

• Standalone - Immutable, no proxy
• Upgradeable - Transparent/Beacon/UUPS proxy patterns
• Light - Minimal for stablecoins
• Allowlist - Whitelist-based transfers (KYC)
• Debt - Bond-specific fields (maturity, coupon)
• DebtEngine - Debt with external engine
• ERC-7551 - German eWpG compliance
• ERC-1363 - transferAndCall support

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Architecture Highlights

1. Modular composition - Mix-and-match features via inheritance
2. Engine pattern - External contracts for complex logic (RuleEngine, SnapshotEngine, DocumentEngine, DebtEngine)
3. ERC-7201 storage - Namespaced storage for safe upgrades
4. Role-based access control - Granular permissions (not single owner)
5. 10+ standard compliance - ERC-20, ERC-3643, ERC-7551, ERC-2771, ERC-7802, etc.

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Contract Inheritance Hierarchy

CMTATBaseCore (0) - Basic ERC20 + Mint + Burn + Validation + Access Control
    ↓
CMTATBaseAccessControl (1) - RBAC roles management
    ↓
CMTATBaseRuleEngine/Allowlist (2) - Transfer validation rules
    ↓
CMTATBaseERC1404 (3) - ERC-1404 compliance (restrictedTransfer)
    ↓
CMTATBaseERC20CrossChain (4) - CCIP & ERC-7802 support
    ↓
CMTATBaseERC2771 (5) - Gasless meta-transactions
    ↓
CMTATBaseERC1363/ERC7551 (6) - Additional standards

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Key Roles (Access Control)

• DEFAULT_ADMIN_ROLE - Admin access (can grant/revoke roles)
• MINTER_ROLE - Can mint tokens
• BURNER_ROLE - Can burn tokens
• PAUSER_ROLE - Can pause/unpause contract
• ENFORCER_ROLE - Can freeze/unfreeze addresses

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Key Files to Understand

• contracts/modules/0_CMTATBaseCore.sol - Core base contract
• contracts/deployment/CMTAT_*.sol - Pre-composed deployment variants
• contracts/interfaces/ - All supported interfaces and standards
• hardhat.config.js - Build configuration
• package.json - Dependencies and scripts