User state transition

There are three steps in user state transition (see user state transition proof), and they should be performed in order.

Start user state transition

/**
* @dev User submit a start user state transition proof
* publicSignals[0] = [ blindedUserState ]
* publicSignals[1] = [ blindedHashChain ]
* publicSignals[2] = [ globalStateTree ]
* @param publicSignals The public signals of the start user state transition proof
* @param proof The The proof of the start user state transition proof
*/
function startUserStateTransition(
    uint256[] memory publicSignals,
    uint256[8] memory proof
) external 

source: Unirep.sol/startUserStateTransition

After start user state transition proof event is emitted, the proof will be assign a proof index, which will be attached to updateUserStateRoot function.

The proof index can be queried by proof hash. And the proof hash can be computed by

ethers

Generate proof hash from ethers

import ethers from 'ethers'

const proofHash = ethers.utils.solidityKeccak256(
    ['uint256[]', 'uint256[8]'],
    [publicSignals, proof]
)

@unirep/contracts

Generate proof hash from @unirep/contracts

import { StartTransitionProof } from '@unirep/contracts'

const proof = new StartTransitionProof(
    publicSignals,
    proof
)
const proofHash = proof.hash(()

Then call the UniRep smart contract to query the proof index

const unirepContract = new ethers.Contract(address, abi, provider)
const index = await unirepContract.getProofIndex(
    proofHash
)

Process attestations

/**
* @dev User submit a process attestations proof
* publicSignals[0] = [ outputBlindedUserState ]
* publicSignals[1] = [ outputBlindedHashChain ]
* publicSignals[2] = [ inputBlindedUserState ]
* @param publicSignals The public signals of the process attestations proof
* @param proof The process attestations proof
*/
function processAttestations(
    uint256[] memory publicSignals,
    uint256[8] memory proof
) external

source: Unirep.sol/processAttestations

After process attestations proof event is emitted, the proof will be assign a proof index, which will be attached to updateUserStateRoot function.

The proof index can be queried by proof hash. And the proof hash can be computed by

ethers

Generate proof hash from ethers

import ethers from 'ethers'

const proofHash = ethers.utils.solidityKeccak256(
    ['uint256[]', 'uint256[8]'],
    [publicSignals, proof]
)Generate proof hash from @unirep/contracts

@unirep/contracts

Generate proof hash from @unirep/contracts

import { ProcessAttestationsProof } from '@unirep/contracts'

const proof = new ProcessAttestationsProof(
    publicSignals,
    proof
)
const proofHash = proof.hash(()

Then call the UniRep smart contract to query the proof index

const unirepContract = new ethers.Contract(address, abi, provider)
const index = await unirepContract.getProofIndex(
    proofHash
)

User State Transition

/**
* @dev User submit the latest user state transition proof
* publicSignals[0] = [ newGlobalStateTreeLeaf ] 
* publicSignals[1:  numEpochKeyNoncePerEpoch] = [ epkNullifiers ] 
* publicSignals[1+  numEpochKeyNoncePerEpoch] = [ transitionFromEpoch ] 
* publicSignals[2+  numEpochKeyNoncePerEpoch: 
                3+  numEpochKeyNoncePerEpoch] = [ blindedUserStates ] 
* publicSignals[4+  numEpochKeyNoncePerEpoch] = [ fromGlobalStateTree ] 
* publicSignals[5+  numEpochKeyNoncePerEpoch:
                4+2*numEpochKeyNoncePerEpoch] = [ blindedHashChains ] 
* publicSignals[5+2*numEpochKeyNoncePerEpoch] = [ fromEpochTree ] 
* @param publicSignals The the public signals of the user state transition proof
* @param proof The proof of the user state transition proof
* @param proofIndexRecords The proof indexes of the previous start transition proof and process attestations proofs
*/
function updateUserStateRoot(
    uint256[] memory publicSignals,
    uint256[8] memory proof,
    uint256[] memory proofIndexRecords
) external 

source: Unirep.sol/updateUserStateRoot

The proofIndexRecords is the proof indexes of all startTransitionProof and processAttestationsProof that are submitted sequentially. See Start user state transition and Process attestations.