A place for developers to talk about building on Farcaster.

/dev

Bad news: To make EIP 712 signatures work in Go, you have to manually increment the 65th byte of the signature by 27 to make it work (!!)

Good news: Github Co-pilot knows this, and auto completed `sig[64] += 27` at the end of my function without me prompting (or even knowing about this)

2 years ago, after i shipped v0 of my previous project, my lead investor got back to me saying that the app doesn't work for him

i received similar feedback from other users, turned out people with ledgers cannot login

so i wrote this code

had no idea what it does then, i have no idea what it does now

but it worked

Yeah, it turns out this hack appears in more places than you would expect (it's not just Go).

Building @warpcast and @farcaster. Previously Coinbase, Brigade, Causes.

Yeah, it turns out this hack appears in more places than you would expect (it's not just Go).

https://github.com/safe-global/safe-core-sdk/blob/4d1c0e14630f951c2498e1d4dd521403af91d6e1/packages/protocol-kit/src/utils/signatures/utils.ts#L91

I think the final puzzle in a contest Base hosted during ETHDenver was based on this quirk. At the time, chatgpt couldn’t solve it.

Yeah it's not a go thing but I have that code too. The issue is that ledger doesn't follow the Ethereum yellow paper, which specifies to add 27 to the v value of the signature, which was a holdover from Bitcoin and embellished with EIP 155