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

StateAqNotMerged

error StateAqNotMerged()

MessageAqNotMerged

error MessageAqNotMerged()

InvalidProcessMessageProof

error InvalidProcessMessageProof()

VkNotSet

error VkNotSet()

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

Name	Type	Description

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

Name	Type	Description

poll

contract IPoll poll

verifier

contract IVerifier verifier

vkRegistry

contract IVkRegistry vkRegistry

constructor

constructor(address _verifier, address _vkRegistry, address _poll) public payable

Create a new instance

Parameters

Name	Type	Description
_verifier	address	The Verifier contract address
_vkRegistry	address	The VkRegistry contract address
_poll	address	The Poll contract address

processMessages

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

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

Parameters

Name	Type	Description
_newSbCommitment	uint256	The new state root and ballot root commitment after all messages are processed
_proof	uint256[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

Name	Type	Description
_currentMessageBatchIndex	uint256	The batch index of current message batch
_messageRoot	uint256	The message tree root
_currentSbCommitment	uint256	The current sbCommitment (state and ballot)
_newSbCommitment	uint256	The new sbCommitment after we update this message batch
_messageTreeSubDepth	uint8	The message tree subdepth
_messageTreeDepth	uint8	The message tree depth
_voteOptionTreeDepth	uint8	The vote option tree depth
_proof	uint256[8]	The zk-SNARK proof

Return Values

Name	Type	Description
isValid	bool	Whether 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

Name	Type	Description
_currentMessageBatchIndex	uint256	The batch index of current message batch
_messageRoot	uint256
_numSignUps	uint256	The number of users that signup
_numMessages	uint256	The number of messages
_currentSbCommitment	uint256	The current sbCommitment (state and ballot root)
_newSbCommitment	uint256	The new sbCommitment after we update this message batch
_messageTreeSubDepth	uint8	The message tree subdepth
_voteOptionTreeDepth	uint8

Return Values

Name	Type	Description
inputHash	uint256	Returns 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

Name	Type	Description
_currentMessageBatchIndex	uint256	batch index of current message batch
_numSignUps	uint256	number of users that signup
_numMessages	uint256	number of messages
_messageTreeSubDepth	uint8	message tree subdepth
_voteOptionTreeDepth	uint8	vote option tree depth

Return Values

Name	Type	Description
result	uint256	The packed value

updateMessageProcessingData

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

update message processing state variables

Parameters

Name	Type	Description
_newSbCommitment	uint256	sbCommitment to be updated
_currentMessageBatchIndex	uint256	currentMessageBatchIndex to be updated
_processingComplete	bool	update flag that indicate processing is finished or not