Implement EIP-712 Typed Data

[peterbroadhurst]

Summary

• Clean Apache 2.0 implementation of https://eips.ethereum.org/EIPS/eip-712
  • Initial implementation believed to contain all core features
• Re-uses the ABI encoding libraries in this repo wherever possible, for consistent encoding/parsing behavior
  • Had to expose a couple of new side-doors to the ABI package to do this - other consumers could use these too
• Operation compared with ISC License reference implementation in TypeScript:
  • See https://github.com/MetaMask/eth-sig-util/blob/main/src/sign-typed-data.ts
  • See PR ERC-712: Expanded on reference type encoding ethereum/EIPs#2190 against standard (never merged)
• Implements V4 derivation of the behavior, as adopted by Metamask and OpenZeppelin communities
  • Most questions in the spec resolved through behavior of above reference implementation
• Extends the ethsigner.Wallet interface with ethsigner.WalletTypedData
  • Avoids existing wallet implementations being forced to change
• Extends the fswallet.Wallet implementation to include SignTypedDataV4
• Contains some general maintenance on the repo
  • Updates firefly-common
  • Updates to Go 1.20
  • Updates dependencies
• Provides mapping of ABI types to EIP-712 type arrays
  • Feels like the tooling around EIP-712 requires quite a bit of hand-spinning for the Solidity developer, and I was thinking this could take away at least one potential source of mistakes, and remove a 3rd artifact to maintain (Solidity struct/ABI, Solidity EIP-712 signing construct on-chain, JSON EIP-712 type array off-chain). Maybe even allow alternative APIs to be built that take ABI type definitions to sign directly.

Outstanding conversations

• EIP-712 original standard includes this comment:

  Note that the v parameter includes the chain id as specified in EIP-155.

  • I did not find evidence that this is adopted. Instead, there is strong guidance to use chainId in the EIP712Domain structure, where it can be verified on-chain using the current block.chainId.
  • As a result, the ethsigner.SignTypedDataV4 code does not call sig.UpdateEIP155(chainID)

[peterbroadhurst]

@awrichar - looks like there's a DCO issue on the initial commit. Will work with you to get that resolved.

[codecov-commenter]

Codecov Report

Attention: 3 lines in your changes are missing coverage. Please review.

Comparison is base (e4d4a70) 100.00% compared to head (04de049) 99.90%.
Report is 5 commits behind head on main.

Files	Patch %	Lines
pkg/rpcbackend/backend.go	57.14%	2 Missing and 1 partial ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##              main      #51      +/-   ##
===========================================
- Coverage   100.00%   99.90%   -0.10%     
===========================================
  Files           35       38       +3     
  Lines         3015     3317     +302     
===========================================
+ Hits          3015     3314     +299     
- Misses           0        2       +2     
- Partials         0        1       +1     

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[peterbroadhurst]

This was required due to resty update

[awrichar]

FYI: I went back to add signoff on my commit, then replayed all of @peterbroadhurst 's commits on top. Should be unchanged in terms of the actual code changes.

[nguyer]

Just a quick question about error codes with a possible duplicate, but happy to merge as is