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Token Registry Program on Aleo: a developer's guide

Hello, my name is Heorhii, and today we’ll dive into Aleo’s Token Registry Program — a standardized approach to issuing and managing tokens on the Aleo blockchain. Built as a singleton program, it ensures interoperability while following Aleo's on-chain restrictions on dynamic calls.

This article walks through its key features, usage, and implementation with practical code snippets.

https://developer.aleo.org/guides/standards/token_registry

1. Understanding the Token Registry Program. The Token Registry Program allows developers to register, mint, transfer, and burn tokens while enabling optional external authorization. This provides flexibility in managing access and permissions.

Key components:

  • Token Registration. Create a new token with unique parameters

  • Minting & Burning. Public & private mint/burn functions

  • Transfers. Support for public and private transfers

  • Access Control. Set roles like Minter, Burner, and Supply Manager

  • External Authorization. Add extra control over spending permissions

Each token is identified by a unique token ID and has metadata stored on-chain.

2. How to use the Token Registry Program:

🔹 Registering a Token. Anyone can register a new token on Aleo by calling:

register_token(
    token_id: field, 
    name: u128, 
    symbol: u128, 
    decimals: u8, 
    max_supply: u128, 
    external_authorization_required: bool, 
    external_authorization_party: address
)

This creates a new token with optional external authorization requirements.

🔹 Minting & Burning Tokens. Once registered, tokens can be minted and burned using the appropriate functions:

mint_public(token_id: field, recipient: address, amount: u128)
mint_private(token_id: field, recipient: address, amount: u128)
burn_public(token_id: field, owner: address, amount: u128)
burn_private(token: Token, amount: u128)

Public transactions are visible on-chain, while private transactions keep ownership confidential.

🔹 Transferring Tokens. Tokens can be moved publicly or privately:

transfer_public(token_id: field, recipient: address, amount: u128)
transfer_private(token: Token, recipient: address, amount: u128)

Additionally, conversions between public and private balances are supported:

transfer_public_to_private(token_id: field, recipient: address, amount: u128)
transfer_private_to_public(token: Token, recipient: address, amount: u128)

🔹 Managing Token roles. The admin can assign specific roles to accounts, such as:

set_role(token_id: field, account: address, role: u8)
remove_role(token_id: field, account: address)

Roles include:

  • Minter – can mint new tokens

  • Burner – can burn tokens

  • Supply Manager – can adjust supply

3. Token Registry data structures. Each token is represented by structured data stored on-chain.

  • Token Record:

record Token {
    owner: address,
    amount: u128,
    token_id: field,
    external_authorization_required: bool,
    authorized_until: u32
}

  • Token Metadata:

struct TokenMetadata {
    token_id: field,
    name: u128,
    symbol: u128,
    decimals: u8,
    supply: u128,
    max_supply: u128,
    admin: address,
    external_authorization_required: bool,
    external_authorization_party: address
}

  • Token Balances:

struct Balance {
    token_id: field,
    account: address,
    balance: u128,
    authorized_until: u32
}

These records enable on-chain tracking of ownership, balances, and authorization conditions.

4. Why use the Token Registry Program? Aleo’s privacy-first approach makes it ideal for secure, compliant token issuance. This registry provides:

  • Standardization. Ensures compatibility across Aleo dApps

  • Privacy control. Supports private transactions

  • Flexible authorization. Optional external approval for extra security

  • Role-based access. Fine-tuned permissions for admins & minters

  • Public & Private transfers. User choice for visibility

The Token Registry Program simplifies token management on Aleo, providing a flexible and privacy-preserving approach to handling digital assets.

Whether you're building a DeFi protocol, gaming platform, or loyalty rewards system, this standard ensures seamless token operations with privacy at its core.

For more details, check out the official source code here.

https://github.com/demox-labs/aleo-standard-programs/blob/main/token_registry/src/main.leo

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Prepared by Colliseum