Doro

The Future of Fair Lottery Systems

Relate Repo & Demo Link

• Mobile App

Contracts

• Old Berkeley ZKapp: 62qrmRifvNnkRaKqw62Z84JGS5dn6cAgvZtLXsDpRLRH4zrxjLhCti

Problem & Solution

• Secure and Participative: Doro revolutionizes lottery systems with advanced cryptographic technology. At its core is the ElGamal homomorphic encryption algorithm, ensuring absolute security and fairness.

• How It Works: Each participant's entry is encrypted using ElGamal, a homomorphic encryption method. This encrypted data is then multiplied with a number on the blockchain. This unique process introduces a high level of randomness, making the lottery outcomes truly unpredictable.

• Fairness and Transparency: Prior to the draw, no one knows the sequence of entries, guaranteeing a level playing field for all participants. Doro's use of Zero-Knowledge Proofs (ZKPs) alongside homomorphic encryption further enhances fairness and transparency, allowing for verifiable draws without compromising individual privacy.

• User Engagement: Our system not only ensures fair play but also increases user engagement. Participants can trust the process, knowing their chances are as random and secure as the technology behind it.

• Conclusion: Doro is more than a lottery system; it's a testament to how cryptography can transform user experience and trust in digital platforms. Join us in embracing a new era of fair, secure, and engaging lottery systems.

Tech Stack

• Mina Protocal: Berkeley Contract
• o1js-elgamal: for encrypt random value
• react native: build hybrid mobile application
• express: mobile interact with chain

Build & Infra

Doro is a monorepo managed using turbo. You can find the source code for each package in the apps and packages directory.

• apps/backend
• apps/serverless (not yet online)
• packages/contract

Tech Architecture

sequenceDiagram
    actor A as Admin
    actor U as User
    participant C as O1js-Contract
    participant E as O1js-elgamal
    participant M as Mina

    %% Compile
    A ->> C: Compile Mental Contract
    C ->> M: Deploy Contract
    
    %% Contract
    A ->> E: Create Public Key and Secret
    E ->> C: Store Public Key on chain
    C ->> M: Prove and Write Data
    
    %% Shuffle
    C ->> U: Get Public Key
    U ->> E: Encrypt Secret Value
    U ->> C: Shuffle and change the random value

    %% Reveal
    A ->> C: Decrypt with secret
    C -->> A: Get Decrypt random value and choose the ans from public set

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