Off-chain signatures in UI

[usmfum]

Off-chain signatures in UI

[jacob-eliosoff]

This is over my head but fewer clicks = good!

[alcueca]

We use off-chain signatures for ERC20Permit and for Delegable.

The way this could be implemented is by creating an onboard function in the frontend that collects the signatures to issue MAX permits for USM to receive/burn USM and FUM, and submits them in a single transaction executed by Proxy. The same process should collect the signatures to execute an addDelegate of Proxy by the user.

Be aware that right now an addDelegate call or signature is required for each one of the four main USM functions. That's bad UX and I'm planning to fix it by coding a batchDelegateByPermit(address holder, address delegate, bytes4[] signature, uint expiry, uint8 v, bytes32 r, bytes32 s) function in Delegable.sol.

So the final process would be:

Click onboard:
 -> USM Permit Signature
 -> FUM Permit Signature
 -> Proxy Delegate Signature
 -> Submit Transaction

The UI can work with Ether by default. An option to use Weth if present could be added somewhere, which would involve a weth.approve(USM.address, MAX) transaction by the user enabling the feature.

[alexroan]

Thanks, @albertocuestacanada. We may have to sync up when this comes around.

This is dependent on #30 being resolved first.