OKTC needs to parse and handle transactions routed for both the EVM and for the Cosmos hub. We attempt to achieve this by mimicking Geth’s Transaction structure and treat it as a unique Cosmos SDK message type. An Ethereum transaction is a single sdk.Msg contained in an auth.StdTx. All relevant Ethereum transaction information is contained in this message. This includes the signature, gas, payload, etc.

Being that OKTC implements the Tendermint ABCI application interface, as transactions are consumed, they are passed through a series of handlers. Once such handler, the AnteHandler, is responsible for performing preliminary message execution business logic such as fee payment, signature verification, etc. This is particular to Cosmos SDK routed transactions. Ethereum routed transactions will bypass this as the EVM handles the same business logic.

Ethereum routed transactions coming from a Web3 source are expected to be RLP encoded, however all internal interaction between OKTC and Tendermint will utilize one of the supported encoding formats: Protobuf and Amino.

Transaction formats#

  • Cosmos transactions
  • Ethereum transaction


OKTC supports EIP-155 signatures. A Transaction is expected to have a single signature for Ethereum routed transactions. However, just as in Cosmos, OKTC will support multiple signers for non-Ethereum transactions. Signatures over the Transaction type are identical to Ethereum and the signatures will not be duplicated in the embedding auth.StdTx.