Overview

Fireblocks lets you create contract call transactions for calling specific functions of contracts on EVM blockchains. You can configure a Contract Call Policy to control which users can call smart contract functions and under which circumstances.

Using the Contract call methods parameter, you can define which specific functions in the smart contract can be called. This allows you to have more control over your Web3 and Decentralized Finance (DeFi) operations as well as the smart contracts you manage from your workspace.

Contract call decoding

Contract call details are recorded as hexadecimal encoded strings. To determine the details of a contract and which functions are being called, Fireblocks decodes contract calls using the contract’s Application Binary Interface (ABI), which is verified on the relevant block explorer. This also allows the appropriate Policy rules to be applied.

If a contract does not have a verified ABI, calls to it will not be decoded. In this case, try to verify it here, and if you are still facing issues, contact Fireblocks Support.

Creating a Policy rule for a specific method

1. Whitelist the smart contract’s address using the Contract type.
2. Create a Contract Call Policy rule, and specify the relevant whitelisted contract address as the destination.
3. In the Contract call methods parameter, enter the functions you want this rule to apply to. You can apply the rule to any function you enter or to the exact list of functions.
4. Configure the remainder of the Policy rule as necessary.

Either or Exact list

Some contract calls can call more than one function in the same transaction. This could be for calling two different functions or as part of a more complicated logic. For example, some contracts use the multicall function to call additional functions. In order to whitelist specific functions in this contract, the multicall function and the other desired function should be defined in your Policy rule.

When entering multiple functions for a Policy rule, you can choose how the rule should be applied to them.

• Either: the rule applies to any call that is made to ANY of the chosen functions
• Exact list: the rule only applies if all of the functions (and no other functions) are part of the call

In the example above:

• if a call is made to function execute(bytes,bytes[]), the rule will apply.
• if a call is made to function execute(bytes,bytes[],uint256), the rule will apply.
• if a call is made to both functions, the rule will not apply.

In the example above:

• if a call is made to function execute(bytes,bytes[]), the rule will not apply.
• if a call is made to function execute(bytes,bytes[],uint256), the rule will not apply.
• if a call is made to both functions and also mint(address,uint256), the rule will not apply.
• if a call is made to both functions, the rule will apply.

Using contract call methods for tokenization

Configuring Policy rules for contract call methods can also be helpful for tokenization. The Fireblocks Tokenization feature allows you to deploy and manage contracts for your custom tokens. When managing your tokens, you can use the Fireblocks Console to call specific functions, such as minting tokens, pausing the contract, transferring ownership, and more.

Using the Contract call methods parameter when creating Policy rules gives you more granular control over these complex operations. You can determine which users are allowed to call which functions, create user groups to control more sensitive operations, and manage your risk profile accordingly.