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Version: v2.0_alpha

MessageProcessor

MessageProcessor is used to process messages published by signup users. It will process message by batch due to large size of messages. After it finishes processing, the sbCommitment will be used for Tally and Subsidy contracts.

NoMoreMessages

error NoMoreMessages()

custom errors

StateNotMerged

error StateNotMerged()

MessageAqNotMerged

error MessageAqNotMerged()

InvalidProcessMessageProof

error InvalidProcessMessageProof()

MaxVoteOptionsTooLarge

error MaxVoteOptionsTooLarge()

NumSignUpsTooLarge

error NumSignUpsTooLarge()

CurrentMessageBatchIndexTooLarge

error CurrentMessageBatchIndexTooLarge()

BatchEndIndexTooLarge

error BatchEndIndexTooLarge()

TREE_ARITY

uint256 TREE_ARITY

processingComplete

bool processingComplete

Get the result of whether there are unprocessed messages left

Return Values

NameTypeDescription

numBatchesProcessed

uint256 numBatchesProcessed

The number of batches processed

currentMessageBatchIndex

uint256 currentMessageBatchIndex

The current message batch index. When the coordinator runs processMessages(), this action relates to messages currentMessageBatchIndex to currentMessageBatchIndex + messageBatchSize.

sbCommitment

uint256 sbCommitment

Get the commitment to the state and ballot roots

Return Values

NameTypeDescription

poll

contract IPoll poll

verifier

contract IVerifier verifier

vkRegistry

contract IVkRegistry vkRegistry

mode

enum DomainObjs.Mode mode

constructor

constructor(address _verifier, address _vkRegistry, address _poll, address _mpOwner, enum DomainObjs.Mode _mode) public payable

Create a new instance

Parameters

NameTypeDescription
_verifieraddressThe Verifier contract address
_vkRegistryaddressThe VkRegistry contract address
_polladdressThe Poll contract address
_mpOwneraddressThe owner of the MessageProcessor contract
_modeenum DomainObjs.ModeVoting mode

processMessages

function processMessages(uint256 _newSbCommitment, uint256[8] _proof) external

Update the Poll's currentSbCommitment if the proof is valid.

Parameters

NameTypeDescription
_newSbCommitmentuint256The new state root and ballot root commitment after all messages are processed
_proofuint256[8]The zk-SNARK proof

verifyProcessProof

function verifyProcessProof(uint256 _currentMessageBatchIndex, uint256 _messageRoot, uint256 _currentSbCommitment, uint256 _newSbCommitment, uint8 _messageTreeSubDepth, uint8 _messageTreeDepth, uint8 _voteOptionTreeDepth, uint256[8] _proof) internal view returns (bool isValid)

Verify the proof for processMessage

used to update the sbCommitment

Parameters

NameTypeDescription
_currentMessageBatchIndexuint256The batch index of current message batch
_messageRootuint256The message tree root
_currentSbCommitmentuint256The current sbCommitment (state and ballot)
_newSbCommitmentuint256The new sbCommitment after we update this message batch
_messageTreeSubDepthuint8The message tree subdepth
_messageTreeDepthuint8The message tree depth
_voteOptionTreeDepthuint8The vote option tree depth
_proofuint256[8]The zk-SNARK proof

Return Values

NameTypeDescription
isValidboolWhether the proof is valid

genProcessMessagesPublicInputHash

function genProcessMessagesPublicInputHash(uint256 _currentMessageBatchIndex, uint256 _messageRoot, uint256 _numSignUps, uint256 _numMessages, uint256 _currentSbCommitment, uint256 _newSbCommitment, uint8 _messageTreeSubDepth, uint8 _voteOptionTreeDepth) public view returns (uint256 inputHash)

Returns the SHA256 hash of the packed values (see genProcessMessagesPackedVals), the hash of the coordinator's public key, the message root, and the commitment to the current state root and ballot root. By passing the SHA256 hash of these values to the circuit as a single public input and the preimage as private inputs, we reduce its verification gas cost though the number of constraints will be higher and proving time will be longer.

Parameters

NameTypeDescription
_currentMessageBatchIndexuint256The batch index of current message batch
_messageRootuint256
_numSignUpsuint256The number of users that signup
_numMessagesuint256The number of messages
_currentSbCommitmentuint256The current sbCommitment (state and ballot root)
_newSbCommitmentuint256The new sbCommitment after we update this message batch
_messageTreeSubDepthuint8The message tree subdepth
_voteOptionTreeDepthuint8

Return Values

NameTypeDescription
inputHashuint256Returns the SHA256 hash of the packed values

genProcessMessagesPackedVals

function genProcessMessagesPackedVals(uint256 _currentMessageBatchIndex, uint256 _numSignUps, uint256 _numMessages, uint8 _messageTreeSubDepth, uint8 _voteOptionTreeDepth) public pure returns (uint256 result)

One of the inputs to the ProcessMessages circuit is a 250-bit representation of four 50-bit values. This function generates this 250-bit value, which consists of the maximum number of vote options, the number of signups, the current message batch index, and the end index of the current batch.

Parameters

NameTypeDescription
_currentMessageBatchIndexuint256batch index of current message batch
_numSignUpsuint256number of users that signup
_numMessagesuint256number of messages
_messageTreeSubDepthuint8message tree subdepth
_voteOptionTreeDepthuint8vote option tree depth

Return Values

NameTypeDescription
resultuint256The packed value

updateMessageProcessingData

function updateMessageProcessingData(uint256 _newSbCommitment, uint256 _currentMessageBatchIndex, bool _processingComplete) internal

update message processing state variables

Parameters

NameTypeDescription
_newSbCommitmentuint256sbCommitment to be updated
_currentMessageBatchIndexuint256currentMessageBatchIndex to be updated
_processingCompleteboolupdate flag that indicate processing is finished or not