Ziden Circuits

Cryptographic circuits used in Ziden protocol with some main components: idOwnershipBySignature, stateTransition, credentialAtomicQueryMTP

idOwnershipBySignature.circom

This circuit validate the signature proving the ownership of holder over the identity. It will be used internally by stateTransition.circom and credentialAtomicQueryMTP.circom for authorization thus there is no public inputs

Parameters:

• nLevels: the depth of identity authorization tree

Private Inputs:

• userState: the accumulated root of user.

• Authorization MTP
  userAuthsRoot
  userAuthMTP
  userAuthHi
  userAuthPubX
  userAuthPubY
  

• Other User Roots:
  userClaimsRoot
  userClaimRevRoot
  

• challenge: the message given by the validator to the holder to sign on

• Signature on the given challenge
  challengeSignatureR8x
  challengeSignatureR8y
  challengeSignatureS
  

stateTransition.circom

This circuit validate and commit the change of the identity's state.

Parameters

• idOwnershipLevels: the depth of identity authorization tree

Public Inputs

• userId: ID of user
• oldUserState: the old accumulated root of user
• newUserState: the new accumulated root of user
• isOldStateGenesis: indicate whether it's the first time user transit their state.

Private Inputs

• Authorization MTP
  userAuthsRoot
  userAuthMTP
  userAuthHi
  userAuthPubX
  userAuthPubY
  

• Other User Roots:
  userClaimsRoot
  userClaimRevRoot
  

• Signature on the hash of the old and new states
  challengeSignatureR8x
  challengeSignatureR8y
  challengeSignatureS
  

credentialAtomicQueryMTP.circom

This circuit help the holder operate some queries over their claim, used when the holder wants to demonstrate some statements about their credential data to the verifier

Parameters

• idOwnershipLevels: the depth of identity authorization tree
• issuerLevels: the depth of the claim tree and claim revocation tree
• valueTreeDepth: the depth of the Merkle tree for membership and non-membership operation

Public Inputs

• userId: ID of user
• userState: the accumulated root of user
• challenge: the message given by the validator to the holder to sign on
• issuerID: id of the issuer who grants the claim for the user
• issuerClaimIdenState: the state of the issuer at the moment they granted the claim
• issuerClaimNonRevState: the latest state of the issuer ( the holder has to make sure their claim hasn't been revoked in this state )
• timestamp: required by the verifier, the holder has to make sure that the expiration time specified in the claim hasn't been passed by this value.
• claimSchema: the schemahash of the claim
• slotIndex: the index of the value took out to query on.
• operator: the operator to make the query on the specified value (value set: EQUAL, GREATER_THAN, LESS_THAN, IN, NOT_IN, IN_RANGE)
• determinisiticValue: the value to be compared with the value in the claim.
• mask: the queried value might not occupy the whole slot, so we need a mask to extract the queried value out of the slot.

Private Inputs

• Authorization MTP
  userAuthsRoot
  userAuthMTP
  userAuthHi
  userAuthPubX
  userAuthPubY
  

• Other User Roots:
  userClaimsRoot
  userClaimRevRoot
  

• Signature on the given challenge
  challengeSignatureR8x
  challengeSignatureR8y
  challengeSignatureS
  

• Existence MTP for the claim in the Claim Tree of issuer
  issuerClaim
  issuerClaimMTP
  issuerClaimAuthsRoot
  issuerClaimClaimsRoot
  issuerClaimClaimRevRoot
  issuerClaimIdenState
  

• Non Existence MTP for the claim in the Revocation Tree of issuer
  issuerClaimNonRevMtp
  issuerClaimNonRevMtpNoAux
  issuerClaimNonRevMtpAuxHi
  issuerClaimNonRevMtpAuxHv
  issuerClaimNonRevAuthsRoot
  issuerClaimNonRevClaimsRoot
  issuerClaimNonRevClaimRevRoot
  issuerClaimNonRevState
  

• Inputs for membership and non-membership operation (ignored if the operator is neither IN nor NOT IN) leaf0
  leaf1
  elemsPath0
  elemsPath1
  pos0
  pos1
  operator