drand

anyrand is built on top of drand, an open-source software that enables a consortium of nodes to continuously produce publicly verifiable randomness. drand utilises threshold BLS (Boneh-Lynn-Shacham) signatures, ensuring that the generated randomness is secure and unmanipulable (as BLS produces deterministic signatures). By requiring a subset of nodes to agree before a random value is produced, drand guarantees that no single node can withhold the randomness output, while ensuring high public availability of the produced random numbers.

Swapping out BLS12-381 with BN254

drand originally uses BLS signatures on the BLS12-381 curve. Unfortunately, verifying BLS12-381 signatures in the EVM is not cost-effective until EIP-2537 is included in Pectra. To address this, we implemented BLS on the BN254 curve, which is much more efficiently verifiable within the EVM. This adaptation has been successfully upstreamed into drand v2, allowing drand beacons to be efficiently verifiable in existing EVM implementations.