A place for talking about the Ethereum Virtual Machine on Farcaster.

1/ I've been working on a method to verify Farcaster messages onchain. The GitHub repo is now open-sourced under an MIT license.

https://github.com/pavlovdog/farcaster-solidity

Full-time builder. Pimlico | @33bits | farcaster-solidity. Zero-knowledge and asynchronous transactions evangelist.

3/ This project solves all the intermediate steps required for message parsing and verification:

- Blake3 hashing
- Ed25519 signature verification
- Protobuf message decoding

Other than working with casts, you can also use reactions, followings, and any other messages, used in the Farcaster protocol.

4/ Currently there are 2 problems I’m facing 

- high gas cost
- difficulty to run it on networks other than Optimism Mainnet.

5/ Gas price

At the moment, verifying and decoding a message costs about 1.5-2m gas, which is a lot. This is caused by Blake3 hashing and Ed25519 signature verification, which are not native for EVM. This cost can be dramatically reduced, by wrapping these two operations into a ZK proof.

Interesting! So currently it’s a little tough because L1 block hashes are pretty ephemeral. With more stable block hash you can do a nested storage proof: proof Base storage root on L1, then prove something about L2 using storage root. 

4788 is coming soon and should help.

6/ Cross chain verification

To verify a public key, you have to interact with a KeyRegistry contract, which is deployed only on Optimism Mainnet. Using this project on other networks e.g. @base will require you to implement a custom verification logic.

6/ Cross chain verification

To verify a public key, you have to interact with a KeyRegistry contract, which is deployed only on Optimism Mainnet. Using this project on other networks e.g. @base will require you to implement a custom verification logic.

https://warpcast.com/wilsoncusack/0xfaeebf09

7/ All the contributions are welcome, let me know if you want to work on the stated problems. And a huge shoutout to @kugusha.eth for helping!

2/ A few examples of what you can build using this project:

- An AA wallet, controlled entirely by a Farcaster account (working on it rn 🤓)
- Claimable NFT under certain conditions (eg following an author)
- An onchain proof of Farcaster account (eg user got X likes)

Working on building products with zkTLS. A ruthless empiricist.

http://opacity.network

Advisor @ EV3 Ventures

Yep, zk proofs will definitely reduce gas cost for verification. Running the code on some zkEVM won’t help if you need to use it with common EVM networks.

I suspect it will be a lot better gas wise to use a zkEVM or dsl to verify the hard parts.

First seen by any hub? Can’t see how it can be verified even in the centralised environment.

cc @sin 

What if you need to verify the time the cast was first seen?

The future of account abstraction is modular

This is really cool. At @rhinestone we’ve been exploring zkEmail x Modular smart accounts. If you haven’t already, definitely check out erc7579 and ModuleKit for building unique smart account features. We’d love to jam with you if you want to explore

this is incredibly useful, thank you so much!