Unofficial Scroll ZK EVM Code Review

Transcript

1. Unofficial Scroll ZK EVM
   Code Review
   https://linktr.ee/alexcj96
   

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2. Summary
   - Why ZK EVM works?
   - Architecture
   - Tech stack comparaison
   - Arithmetization
   - Trace generation
   - Gate configuration
   - Circuit tools
   - Some opcode gadgets
   - Public input circuit
   - Synthesize
   - Combining with halo2
   - Observation
   

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3. Why ZK EVM works?
   ❖ EVM is a State Machine
   ❖ Public-key cryptography
   ➢ Verify txs all represent users' intention
   ❖ Blockchain consensus
   ➢ Verifier
   ➢ Previous state root
   ❖ MPT
   ➢ Verify initial state
   ➢ Verify new root
   ❖ ZK
   ➢ Succinctness
   ➢ Lookup Arguments
   ❖ Ethereum as a DA Layer
   

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4. Architecture
   

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5. Tech stack comparaison
   

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6. Arithmetization
   

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7. Trace generation - flow (scroll has simplified this)
   

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8. Trace generation - types (simplified)
   

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9. Gate configuration - flow
   

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10. Gate configuration - gadgets
    Add cb constraints etc
    

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11. Gate configuration - lookup
    

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12. Circuit tools - cell manager
    

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13. Circuit tools - constraint builder
    

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14. Circuit tools - constraint builder
    

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15. Circuit tools - utils
    

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16. Some opcode gadgets - AddSub
    

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17. Some opcode gadgets - ReturnRevert (simplified)
    

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18. Public input circuit
    

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19. Public input circuit
    

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20. Synthesize
    

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21. Combining with halo2
    

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22. Combining with halo2
    

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23. Observation
    - Scroll doesn’t support self destruct EVM opcode
    - Scroll’s MPT tree uses poseidon circuit
    - Scroll uses chain_id and block_number to calculate block_hash!!!
    - Scroll still uses SuperCircuit which is very zk-unfriendly
    - Don’t read PSE’s code, it’s not production ready!!!
    - …
    

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24. Thanks!
    

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