BLS381 Hash to curve

Solidity implementation of hash to curve for the BLS381 curve using the EIP-2537 precompiles.

Follows https://datatracker.ietf.org/doc/html/rfc9380

Tests

forge test
Runs tests against expandMsgXmd and hashToField.
hashToCurve tests exist, but fail because foundry doesn't have EIP support yet.

npm run testjs
Runs hardhat tests for hashToCurve.
Make sure you have an execution client at http://localhost:8545 running that supports the EIP.

All test cases are from the RFC.

Notes

Costs

G1 addition 600 gas G2 addition 4500 gas
Fp-to-G1 mapping 5500 gas (used twice) Fp2-to-G2 mapping 110000 gas (used twice)

g1 total cost:
11600 (precompiles) + 31000 (current hash to field) = ca: 42600
g2 total cost:
234500 (precompiles) + 44000 (current hash to field) =ca: 278500

readable version

This is an old version that follows the RFC very literal and is therefore very easy to understand.

EIPTester

Very simple test to see wether the RPC has EIP-2537 enabled.

Disclaimer

No guarantee for the correctness of the implementation.