Hash to G1 point setting different domain string

[vincenzoiovino]

Hello,
I need the following.
I need to hash to G1 for the BLS12-381 curve using the standard IRTF but with the domain string of G2 rather than G1.
This is because drand has a bug in the implementation: in the hash to G1 use the domain string of G2 .
I could not find how I can modify the domain string programmatically in arkworks.
Any hint?

[hujw77]

https://github.com/darwinia-network/darwinia/blob/main/precompile/bls12-381/src/bls/mod.rs#L95-L102

This uses case might help you.

[burdges]

We need to open up the hash-to-curve anyweays because the IRTF draft permits user specified xofs, everyone hates the sha2 xmd, some curves require other xofs, and our code currently does not support any other xof. I started some PRs for this, but got distracted.