Lanes

The lane mechanism is used to ensure that messages that submit keyshares are executed before other messages to avoid front-running.

Invariants

• The keyshare lane only contains transactions that contain MsgSubmitDecryptionKey messages.

• The default lane does not contain any transactions with MsgSubmitDecryptionKey messages.

Test coverage

The tests in abci/checktx/check_tx_test.go test inserting transactions into a mempool that makes use of the lane mechanism. The tests in lanes/keyshare/utils_test.go test that transactions are encoded consistently with block-sdk, which the lane mechanism uses.

Attack surface

PrepareLaneHandler

The PrepareLaneHandler function is called as part of PrepareProposal by the block proposer. It extracts transactions containing MsgSubmitDecryptionKey from the mempool and places them in the KeyshareLane, validating them with VerifyTx, and discarding transactions that exceed MaxTxBytes.

ProcessLaneHandler

The ProcessLaneHandler function is called as part of ProcessProposal by all validators. It ensures that the keyshare lane only contains keyshare transactions and that no non-keyshare transactions are in the default lane.