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TVL: $25.00 M

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Sorare is a global fantasy football game where you can play with officially licensed digital cards and earn prizes every week.

Risk summary


Validity proofs ensure state correctness[Edit][Issue]

Each update to the system state must be accompanied by a ZK Proof that ensures that the new state was derived by correctly applying a series of valid user transactions to the previous state. Once the proof is processed on the Ethereum blockchain the L2 block is instantly finalized. The system state is represented using Merkle roots.[1]

    Zero knowledge STARK cryptography is used[Edit][Issue]

    Despite their production use ZK-STARKs are still new and experimental cryptography. Cryptography has made a lot of advancements in the recent years but all cryptographic solutions rely on time to prove their security.[2]

    • Funds can be stolen if the cryptography is broken or implemented incorrectly.

    Data is not stored on chain[Edit][Issue]

    The balances of the users are not published on-chain, but rather sent to several well known and trusted parties, also known as committee members. A state update is valid and accepted on-chain only if at least a quorum of the committee members sign a state update.[3][4]

    • Funds can be lost if the external data becomes unavailable.
    • Users can be censored if the committee restricts their access to the external data.


    The system has a centralized operator[Edit][Issue]

    The operator is the only entity that can propose blocks. A live and trustworthy operator is vital to the health of the system. Typically, the Operator is the hot wallet of the StarkEx service submitting proofs for state updates.[5]

    • MEV can be extracted if the operator exploits their centralized position and frontruns user transactions.

    Users can force exit the system[Edit][Issue]

    Force exit allows the users to escape censorship by withdrawing their funds. The system allows users to force the withdrawal of funds by submitting a request directly to the contract on-chain. The request must be served within a defined time period. If this does not happen, the system will halt regular operation and permit trustless withdrawal of funds.[6]

    • Users can be censored if the operator refuses to include their transactions. They can still exit the system.


    Regular exit[Edit][Issue]

    The user initiates the withdrawal by submitting a transaction on L2. When the block containing that transaction is proven the funds become available for withdrawal on L1. Finally the user submits an L1 transaction to claim the funds. This transaction does not require a merkle proof. When withdrawing NFTs they are minted on L1.[7]

      Forced exit[Edit][Issue]

      If the user experiences censorship from the operator with regular exit they can submit their withdrawal requests directly on L1. The system is then obliged to service this request. Once the force operation is submitted if the request is serviced the operation follows the flow of a regular exit.[8][9][10]

        Emergency exit[Edit][Issue]

        If enough time passes and the forced exit is still ignored the user can put the system into a frozen state, disallowing further state updates. In that case everybody can withdraw by submitting a merkle proof of their funds with their L1 transaction.[8][9][10]

          Smart Contracts[Edit][Issue]

          The system consists of the following smart contracts:

          The current deployment carries some associated risks:

          • Funds can be stolen if a contract receives a malicious code upgrade. There is a 14 days delay on code upgrades.


          1. Enforcing Consistency on the On-Chain State - StarkEx documentation
          2. Stark Curve - StarkEx documentation
          3. Validium - StarkEx documentation
          4. Availability Verifiers - StarkEx documentation
          5. Operator - StarkEx documentation
          6. Censorship Prevention - StarkEx documentation
          7. Withdrawal - StarkEx documentation
          8. Forced Operations - StarkEx documentation
          9. Forced Withdrawal - StarkEx documentation
          10. Full Withdrawal - StarkEx documentation