Approval with Smart Contracts

When configured for smart contract mode for approvals, the Virtual Signer will invoke the functions of
a smart contract to approve, reject, or abstain from voting on or signing requests.

ApprovalNodeRPCAddress in the Virtual Signer configuration refers to the RPC URL of an Ethereum or io.network node.
ApprovalSmartContractAddress in configuration refers to the address of the smart contract that implements the approval logic.

The smart contract must have three functions with the following signatures:

function approvedKeygenReshare(bytes memory encodedKeygenReshare) public pure returns (uint8)
function approvedTx(bytes memory encodedTx) public pure returns (uint8)
function approvedSignOp(bytes memory encodedSignOp) public pure returns (uint8)

The functions are invoked by the Virtual Signer with ABI encoded tuples that represent a keygen or reshare request, a transaction signing request or a sign operation request. Each function returns one of these values:

uint8 public constant APPROVE = 0;
uint8 public constant REJECT = 1;
uint8 public constant ABSTAIN = 2;

The structs that represent reshares, transaction and sign operation requests are defined in the sample contracts below on our public GitHub pages. Follow the link to see them.

Sample Smart Contracts

You may find a public sample approval contract here on GitHub . Be sure to use the structs, and keep the same method signatures, in your own implementation to ensure compatibility with the Virtual Signer.

Getting it Running

Be sure to set the following Configuration Items on your Virtual Signer to get it pointed to your deployed contract, then restart the instance for the changes to take effect:

• EDG_VS_ApprovalNodeRPCAddress
• EDG_VS_ApprovalSmartContractAddress