Added `latest_vdf_outputs` in `state` initialised to an array of `ZERO_HASH` of length `LATEST_RANDAO_MIXES_LENGTH // EPOCH_LENGTH`. (There's one VDF output per epoch. The VDF input is the RANDAO mix at the epoch boundary.)
Further changes to activate VDFs (in a future phase):
* Add a new beacon "VDF output and proof" transaction, e.g. with `MAX_VDF_OUTPUT_AND_PROOF := 1`.
* Adjust the `MAX_SEED_LOOKAHEAD` constant, e.g. to `2**4 * EPOCH_LENGTH`. (The `2**4` parameter is essentially `A_max`.)
* Add a `process_vdf_output_and_proof` helper function in the per-block processing:
* Verify the VDF input hasn't already been processed (check the corresponding `state.latest_vdf_outputs` entry is not `ZERO_HASH`.)
* Verify the proof is correct, i.e. matches the VDF input and output
* Save the VDF output to `state.latest_vdf_outputs`
* In the per-epoch processing set the corresponding entry in `state.latest_vdf_outputs` to `ZERO_HASH`.
* Use a VDF output for the shuffling seed.
* Fixes parameters and makes clear that the inactivity leak is on a per-epoch basis (before the leak was technically 64 times too weak as it was calculated per-slot but applied per-epoch)
* Adds a `// 2` to the inactivity leak to compensate for it being applied twice
* Changes how it is calculated (no inactivity leak for not being part of the head, only basic leak)
* Separates out early inclusion incentives into a separate incentive component rather than being multiplicative with everything else
Slight simplification. Only substantive change is that if the validator registry stays constant, we don't reshuffle 3 epochs after the last reshuffling (ie. before the reshufflings happened after 1, 2, 3, 4, 8, 16... epochs, now it's just 1, 2, 4, 8, 16...)
Hsiao-Wei Wang
terence tsao
Danny Ryan
vbuterin
Joseph Delong
Justin
Chih Cheng Liang
Akhila Raju
Anirudha Bose
Dan Burnett