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LEARN DEVELOPER NODE OPERATOR GRANTS

Circuits

Arithmetic Circuits allow for zero-knowledge (ZK) operations, and are used e.g., by our genesis contracts for these specific use-cases:

  • Phoenix: to spend notes and pay for gas.
  • Citadel: to use in the Self-Sovereign Identity implementation.
  • Zedger: to use the Zedger transaction model and spent securities.

Developers can write their own ZK circuits as part of their smart contracts, allowing for the proving and verification of zero-knowledge proofs.

Phoenix circuits

Circuits in Phoenix prove that the following conditions hold true:

  1. Membership: Every note that is about to be spent is included in the Merkle tree of notes.
  2. Ownership: The sender holds the note secret key for every note that is about to be spent.
  3. Nullification: The nullifier is calculated correctly.
  4. Minting: The value commitment for the newly minted notes are computed correctly.
  5. Balance integrity: The sum of the values of all spent notes is equal to the sum of the values of all minted notes + the gas fee + a deposit, where a deposit refers to funds being transfered to a contract.

For additional information, you can have a look at the circuits and specifications.

Citadel circuits

Circuits in Citadel allow for the following actions: Request Creation and Encryption:

  1. Stealth Address Generation: A new stealth address is correctly generated using Diffie-Hellman.
  2. Data Encryption: The license stealth address and an additional key are encrypted using the derived key.
  3. Session Initialization: Public inputs are used to construct session data (e.g. session ID, session hash, commitments…).
  4. Verification: Pedersen commitments and hash commitment are calculated and verified.
  5. Data Decryption: Requested data is decrypted using the derived key.
  6. Signature Creation: A signature for the license is generated using the license secret key and hash.
  7. License Data Encryption: The signature and attribute data are encrypted with the public key of the license.
  8. Proof Generation: A proof of membership in a Merkle tree is created.
  9. Proof Verification:: Cryptographic commitments are computed and the signature of the session hash is verified.

For additional information, you can have a look at the circuits and specifications.

Zedger circuits