BeaconDkg

BeaconDkg

This file documents a contract which is not yet deployed to Mainnet.

Parameters

struct Parameters {
  uint256 resultChallengePeriodLength;
  uint256 resultChallengeExtraGas;
  uint256 resultSubmissionTimeout;
  uint256 submitterPrecedencePeriodLength;
}

Data

struct Data {
  contract SortitionPool sortitionPool;
  contract BeaconDkgValidator dkgValidator;
  struct BeaconDkg.Parameters parameters;
  uint256 startBlock;
  uint256 seed;
  uint256 resultSubmissionStartBlockOffset;
  bytes32 submittedResultHash;
  uint256 submittedResultBlock;
}

Result

struct Result {
  uint256 submitterMemberIndex;
  bytes groupPubKey;
  uint8[] misbehavedMembersIndices;
  bytes signatures;
  uint256[] signingMembersIndices;
  uint32[] members;
  bytes32 membersHash;
}

State

enum State {
  IDLE,
  AWAITING_SEED,
  KEY_GENERATION,
  AWAITING_RESULT,
  CHALLENGE
}

groupSize

uint256 groupSize

Size of a group in the threshold relay.

offchainDkgTime

uint256 offchainDkgTime

Time in blocks after which DKG result is complete and ready to be

DkgStarted

event DkgStarted(uint256 seed)

DkgResultSubmitted

event DkgResultSubmitted(bytes32 resultHash, uint256 seed, struct BeaconDkg.Result result)

DkgTimedOut

event DkgTimedOut()

DkgResultApproved

event DkgResultApproved(bytes32 resultHash, address approver)

DkgResultChallenged

event DkgResultChallenged(bytes32 resultHash, address challenger, string reason)

DkgStateLocked

event DkgStateLocked()

DkgSeedTimedOut

event DkgSeedTimedOut()

init

function init(struct BeaconDkg.Data self, contract SortitionPool _sortitionPool, contract BeaconDkgValidator _dkgValidator) internal

Initializes SortitionPool and DKGValidator addresses. Can be performed only once.

Parameters

Name	Type	Description
self	struct BeaconDkg.Data
_sortitionPool	contract SortitionPool	Sortition Pool reference
_dkgValidator	contract BeaconDkgValidator	DKGValidator reference

currentState

function currentState(struct BeaconDkg.Data self) internal view returns (enum BeaconDkg.State state)

Determines the current state of group creation. It doesn't take timeouts into consideration. The timeouts should be tracked and notified separately.

lockState

function lockState(struct BeaconDkg.Data self) internal

Locks the sortition pool and starts awaiting for the group creation seed.

start

function start(struct BeaconDkg.Data self, uint256 seed) internal

submitResult

function submitResult(struct BeaconDkg.Data self, struct BeaconDkg.Result result) external

Allows to submit a DKG result. The submitted result does not go through a validation and before it gets accepted, it needs to wait through the challenge period during which everyone has a chance to challenge the result as invalid one. Submitter of the result needs to be in the sortition pool and if the result gets challenged, the submitter will get slashed.

hasDkgTimedOut

function hasDkgTimedOut(struct BeaconDkg.Data self) internal view returns (bool)

Checks if DKG timed out. The DKG timeout period includes time required for off-chain protocol execution and time for the result publication. After this time a result cannot be submitted and DKG can be notified about the timeout. DKG period is adjusted by result submission offset that include blocks that were mined while invalid result has been registered until it got challenged.

Return Values

Name	Type	Description
[0]	bool	True if DKG timed out, false otherwise.

notifyTimeout

function notifyTimeout(struct BeaconDkg.Data self) internal

Notifies about DKG timeout.

notifySeedTimedOut

function notifySeedTimedOut(struct BeaconDkg.Data self) internal

Notifies about the seed was not delivered and restores the initial DKG state (IDLE).

approveResult

function approveResult(struct BeaconDkg.Data self, struct BeaconDkg.Result result) external returns (uint32[] misbehavedMembers)

Approves DKG result. Can be called when the challenge period for the submitted result is finished. Considers the submitted result as valid. For the first submitterPrecedencePeriodLength blocks after the end of the challenge period can be called only by the DKG result submitter. After that time, can be called by anyone.

Can be called after a challenge period for the submitted result.

Parameters

Name	Type	Description
self	struct BeaconDkg.Data
result	struct BeaconDkg.Result	Result to approve. Must match the submitted result stored during submitResult.

Return Values

Name	Type	Description
misbehavedMembers	uint32[]	Identifiers of members who misbehaved during DKG.

challengeResult

function challengeResult(struct BeaconDkg.Data self, struct BeaconDkg.Result result) external returns (bytes32 maliciousResultHash, uint32 maliciousSubmitter)

Challenges DKG result. If the submitted result is proved to be invalid it reverts the DKG back to the result submission phase.

Can be called during a challenge period for the submitted result.

Parameters

Name	Type	Description
self	struct BeaconDkg.Data
result	struct BeaconDkg.Result	Result to challenge. Must match the submitted result stored during submitResult.

Return Values

Name	Type	Description
maliciousResultHash	bytes32	Hash of the malicious result.
maliciousSubmitter	uint32	Identifier of the malicious submitter.

requireChallengeExtraGas

function requireChallengeExtraGas(struct BeaconDkg.Data self) internal view

Due to EIP150, 1/64 of the gas is not forwarded to the call, and will be kept to execute the remaining operations in the function after the call inside the try-catch.

To ensure there is no way for the caller to manipulate gas limit in such a way that the call inside try-catch fails with out-of-gas and the rest of the function is executed with the remaining 1/64 of gas, we require an extra gas amount to be left at the end of the call to the function challenging DKG result and wrapping the call to BeaconDkgValidator and TokenStaking contracts inside a try-catch.

setParameters

function setParameters(struct BeaconDkg.Data self, uint256 _resultChallengePeriodLength, uint256 _resultChallengeExtraGas, uint256 _resultSubmissionTimeout, uint256 _submitterPrecedencePeriodLength) internal

Updates DKG-related parameters

Parameters

Name	Type	Description
self	struct BeaconDkg.Data
_resultChallengePeriodLength	uint256	New value of the result challenge period length. It is the number of blocks for which a DKG result can be challenged.
_resultChallengeExtraGas	uint256	New value of the result challenge extra gas. It is the extra gas required to be left at the end of the challenge DKG result transaction.
_resultSubmissionTimeout	uint256	New value of the result submission timeout in seconds. It is a timeout for a group to provide a DKG result.
_submitterPrecedencePeriodLength	uint256	New value of the submitter precedence period length in blocks. It is the time during which only the original DKG result submitter can approve it.

complete

function complete(struct BeaconDkg.Data self) internal

Completes DKG by cleaning up state.

Should be called after DKG times out or a result is approved.