Apstark

Apstark is a Layer 2 ZK-Rollup blockchain built on top of the Aptos network.

Repositories

• Madara Orchestrator: A service running alongside Madara to facilitate synchronization between L2 and L1.
• Irelia: A Rust-based Sharp Prover equivalent service for generating and submitting verification proofs.
• Madara: A full node implementation for Starknet.
• Apstark-Kurtosis: A tool for setting up a fully functional devnet.
• Navori: A verifier contract for Apstark.
• Ionia: A contract responsible for data availability in the rollup.
• Stark-EVM Adapter: A library for parsing and manipulating STARK proof outputs, enabling the generation of "split proofs" required for proof verification on Ethereum.
• ORN: A tool for managing contract constants for the verifier.
• ORNN: A tool for synchronizing verifier code between Solidity and Move.

Purpose

This project aims to:

• Explore techniques for building a Layer 2 ZK-Rollup, focusing on both the engineering and research aspects, with an emphasis on the Starknet tech stack.
• Eventually use this stack to develop a Gaming SDK, enabling developers to create games that can handle massive user bases and interactions. More on this here.

Architecture and Full Topology

The following diagram illustrates a simplified (not 100% matching the actual implementation) data flow, starting from when users submit transactions to when those transactions are committed on L1 and achieve "ACCEPTED ON L1" status.

1. Transaction processing within the L2 network (Madara):

   • (1.1): User transactions are placed in the Mempool.
   • (1.2): These transactions are then verified and executed within the SNOS VM.
   • (1.3): A new block is generated containing valid transactions, now marked as "ACCEPTED ON L2".

2. Sending the new block to L1 (Madara Orchestrator):

   • (2.1): The new block, along with the state diff and execution trace, is fetched from Madara (handled by the SNOS job).
   • (2.2): This data is re-evaluated in the SNOS VM to ensure validity.
   • (2.3): The data is used to generate a Cairo proof, which will later be processed by Irelia to create a ZK proof.
   • (2.4): All the data is uploaded to a Data Storage (such as S3) for future use.
   • (2.5): The Proving Job retrieves the necessary data to create a proof job inside Irelia later.

3. Proof generation and upload to Aptos (Irelia):

   • (3.1): The Proving Job sends a request to Irelia to generate proof and upload it to Aptos (L1).
   • (3.2): Upon receiving the request, the controller validates it and saves it in a database.
   • (3.3): The job is picked up by the Proving Job, which inputs the job's Cairo PIE into the Stone Prover to generate the proof ( 3.4, 3.5).
   • (3.6): The proof is then pushed into Aptos via the Navori contract.
   • (3.7): The event listener monitors events and updates the job status in the database (3.8).
   • (3.9, 3.10): The job's result is returned to the Proving Job inside Madara Orchestrator (pulling style).

4. Data availability (Madara Orchestrator):

   • (4.0): After retrieving the job's result, the DA Job picks up the state diff and execution trace from the Proving Job.
   • (4.1): It then uploads the data to the Ionia Smart Contract, receiving the result (4.2).
   • (4.3): It triggers the State Update Job.

5. Final Step (Madara Orchestrator - Navori):

   • (5.1): The State Update Job calls the Navori contract.
   • (5.2, 5.3): Inside Navori, it first calls Ionia to verify that the corresponding data has been uploaded, matching the proof used to update the network state.
   • (5.4): It then verifies the update, transitioning the state to the next block number.
   • (5.5): Finally, Madara picks up these changes and updates the status of related transactions and blocks, marking them as " ACCEPTED ON L1".

Progress - Accomplishments

Note: There are still a few tasks remaining to make it fully available.

Endpoints

• Madara RPC: http://157.66.46.183:9944
• Explorer: http://157.66.46.183:4000

Progress

• Equivalent Verifier Smart Contract functions written in Move. (Progress: 95%)
  • Navori (Progress: 90%)
  • Ionia (Progress: 100%)
• Madara Orchestrator code enabling interaction with Aptos. (Progress: 90%)
• Madara integration code for Aptos interaction. (Progress: 50%)
• Irelia (Sharp Prover equivalent) (Progress: 80%)
• Deployment progress:
  • Aptos network (L1): (Progress: 100%)
  • Madara (L2): (Progress: 100%)
  • Contract deployment: (Progress: 20%)
  • Madara Orchestrator: (Progress: 20%)
  • Other auxiliary services: (Progress: 50%)