Aynrand

This is a Raffle architecture for Sui move language using good practices for modularity and separation of concerns, implementing a raffle system based on the lesson from the book of move https://move-book.com/ , and lessons from the paper "Building Random, Fair, and Verifiable Games on Blockchain" https://arxiv.org/pdf/2310.12305

The name for Aynrand comes from the idea of randomness and fairness, and the fact that the system is not deterministic, but rather random, also the idea of implement a descentralized DRAND Number generator for a next iteration.

System Architecture

Sequence Diagram

sequenceDiagram
    participant Admin
    participant User
    participant RaffleContract
    participant PrizePool

    Admin->>RaffleContract: Create Raffle
    Admin->>RaffleContract: Mint Tickets
    User->>RaffleContract: Buy Ticket
    RaffleContract->>PrizePool: Add Funds
    RaffleContract->>RaffleContract: Draw Winner
    User->>RaffleContract: Claim Prize
    RaffleContract->>PrizePool: Withdraw Funds

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• The Admin begins the raffle by setting it up and creating tickets for people to purchase.
• Users buy these tickets to enter the raffle, and their payments go into the PrizePool.
• Once the raffle is over, the system randomly selects a winner.
• The winner claims their prize, and the prize money is transferred to them from the PrizePool.

A more detailed diagram can be found in the docs

Class Diagram

classDiagram
    class Raffle {
        +UID id
        +TicketVault tickets
        +PrizePool prize
        +RaffleConfig config
        +RaffleState state
        +create()
        +mint_tickets_to_raffle()
        +buy_ticket()
        +draw_winner()
        +claim_prize()
    }

    class TicketVault {
        +Table<address, Ticket> buyed_tickets
        +vector<ID> available_tickets
    }

    class PrizePool {
        +Balance<SUI> balance
        +add_funds()
        +get_amount()
        +withdraw_all()
    }

    class RaffleConfig {
        +u64 start_time
        +u64 end_time
        +address admin
        +u64 price
    }

    class RaffleState {
        +Option<address> winner
        +bool claimed
    }

    Raffle --> TicketVault
    Raffle --> PrizePool
    Raffle --> RaffleConfig
    Raffle --> RaffleState

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A more detailed diagram can be found in the docs

Key Features

• Lifecycle Management: Raffles progress through distinct states (NotStarted → Active → Ended → WinnerDrawn)
• Ticket Management: Administrators can mint and manage ticket distribution
• Prize Pool: Secure handling of SUI tokens for a prize pool
• Random Winner Selection: Uses Sui's Random module for winner selection
• Prize Claims: A Winner can claim their prize after drawing

Technical References

The system uses Sui Move's object model and implements best practices from:

• The Move Book
• "Building Random, Fair, and Verifiable Games on Blockchain"

Technical Insights

Sui is a blockchain that comes from the fork of the Libra development teams by Meta, defining an architecture for Diem, their currency, based on Byzantine Fault Tolerance properties and a BLS scheme through validators for ID assignment and transactional object verification. This is very different from the classic non-scalable blockchain model, as it uses a directed acyclic graph model, allowing for greater scalability and becoming the most componentizable.

Design Decisions, Modularity:

A top-to-bottom approach and a modular architecture were initially considered for greater development flexibility, with the shared object model understood to be the most suitable for creating these structures. An important lesson learned in Move for Sui is that less is more.

Key Learnings

• The assumption of similarity between Rust and Move challenged the initial plan to create a reusable module for testing, and I moved to the test scenario of the Sui framework.
• One of the fundamental features of this language is returning objects that do not have drop, for example, and destroying them one by one.
• Another unique feature is OTW, one-time witness, which simulates a single execution and refers to the concept of a constructor. Regarding defined responsibilities, the raffle handles ticket creation and purchase, as well as prize claim and draw winner. Several structures where composed to enhance understanding and provide versatility to the architecture.

Final thoughts:

Sui can be seen as a great language for defining real-world assets and financial services, as well as for ensuring transparency and identity schemes. Additionally, consume-on-demand models can be derived for storage beyond classic blockchain applications, with a stronger focus on communications. This is made possible by its compatibility with SNARKs and zero-knowledge proofs, which enable new architectures and greater information compression and speed.