Todo

• Need to create a dapp to interact with erc20 contract. Currently using: https://oneclickdapp.com/matrix-second

  • The complexity of this depends on how we structure the ERC20 contract. If we update the contract with all of the fields needed (e.g., passing in a FIO Address to approve) we may be able to use a simple contract explorer.

• Decide on how to pass in FIO Address (see below)

Use case

Unwrap FIO Token:

1. Alice (dApp) executes ERC20 unwrap sending in a hashed FIO Address

2. ERC20 calls burn from Alice’s account

3. Oracle monitors unwrap

4. Oracle calls fio.oracle unwraptokens which transfers FIO to Alice

   1. TBD: Oracle passes in FIO Address or FIO Pub Key?

Diagram link: https://app.diagrams.net/#G1ETfA3K6VTa-rhqcH7gJmRsFUIiGS2kDn

Discussion

Passing FIO Address into approve

• Discussed using (hashed) FIO Address versus FIO Public Key.

  • A hashed address will generally be smaller and is a known fixed size.

  • To use a FIO Pub Key we would need to convert the pub key to a raw ecc pubkey so we can fit it in 32 bytes, otherwise it's 56 -> padded to 64 and we end up adding even more gas

  • The “standard” in FIO is to use FIO Pub Key

  • The oracle does a validation check on the FIO Address

  • Decision: We will pass in a (hashed) FIO Address to the ERC20 contract

  • TBD: Does the oracle pass a FIO pub key into unwrap tokens?

• How to pass in FIO Address

  • The current approach does not modify the ERC20 approve function. It appends the hashed FIO Address to the transaction:

    • Convert the i128 hash to bytes, left pad with zeros until it's 32 bytes long, tack it onto the end of the transaction data, sign and send

    • Here is the encoding: https://github.com/blockpane/fio.oracle/blob/main/internal/util/eth.go#L206

    • An example of sending the data: https://github.com/blockpane/fio.oracle/blob/main/internal/util/eth.go#L423

  • Decision: Adam will create an unwrap function that accepts a hashed FIO Address