TL;DR
At the L* milestone, BLS keys are retired. The current randao_reveal mechanism fails entirely. This post proposes the minimal, hash-based fix: a PRF-commitment VRF derived from the leanSig seed, proved with a standalone WHIR proof included in the BeaconBlockBody. The construction activates at I*, so RANDAO gains quantum resistance before L* rather than at it.
A reference implementation is at GitHub - aryaethn/leanEthereumPostQuantumVRF: Forked repo from "Minimal zkVM, targeting aggregation of hash-based signatures," to create a PQ VRF on top of it. ยท GitHub .
A companion paper is attached pq_vrf_ethereum.pdf (657.8 KB).
Pinging the EF PQ team for review: @JustinDrake @Khovratovich @benedikt-wagner @will-corcoran.
Original discussion can be found at ethresear.ch