Returns the Merkle branch for the leaf at index `index`. This getter provides
an alternative way for beacon chain proposers to access the Merkle tree of
deposits rather than being Ethereum 1.0 light clients. The method can be
called on a trusted Ethereum 1.0 archive node at specific past block numbers
to retrieve the Merkle branch needed to register a validator.
The variable name 'slot' in the for-loop in 'get_shuffling' conflicts with the get_shuffling argument name 'slot'. Renames 'slot' in for-loop to 'slot_num'.
In keeping with the rest of the code in this document we adhere to valid Python
where possible.
The custom comparator keyword argument for `sorted` is `key` so this commit
updates its usage when sorting validators by exit order.
This code determines the order in which the next branch element and the
current value should be hashed to produce the parent node in the Merkle tree.
The existing code fails to verify branches constructed in the standard way.
This patch fixes the spec code so that it works properly by using an appropriate
parity calculation.
Example code here to illustrate it working:
https://gist.github.com/ralexstokes/9d82e188bd3286ff74a1fa1dcb5068e0
`EJECTION_BALANCE` is in units of ETH.
`state.validator_balances[index]` is in units of Gwei.
For the ejection computation to work as desired, we need to convert the
`EJECTION_BALANCE` constant from ETH to Gwei.
There should be a correspondence here but referring to the slot is more
explicit, especially for those who are not as familiar with the
details of FFG finalization.
* Make RANDAO into a hash chain (this makes it easy for applications to prove the intermediate RANDAO reveals).
* Include `state.slot` when shuffle to avoid stale shuffles with skip slots
* Cleanup comments related to custody
* Rename "Miscellaneous" to "Custody" in the table of contents
* Use `INITIAL_SLOT_NUMBER` instead of `0` for initial custody slots
* (typo) Fix `second_latest_custody_reseed_slot` => `penultimate_custody_reseed_slot`
* `processed_deposit_root` => `latest_deposit_root`
* `receipt_root` => `deposit_root`
* `receipt_tree` => `deposit_tree`
* Emphasize that deposits are Ethereum 1.0 deposits in text in various places
* `Eth1Deposit` => `Deposit` for consistency (Also happy sticking with `Eth1Deposit` and replacing `deposit_` with `eth1_deposit_` everywhere. This may be unnecessary since Ethereum 2.0 deposits can be distinguished with the `shard_` prefix, e.g. `ShardDeposit` and `shard_deposit`.)
* Clarify `withdrawal_credentials`.
* Clarify that multiple Ethereum 1.0 blocks can have the same deposit root.
Cleanups
* (typo) Remove `get_new_validator_registry_delta_chain_tip` from table of contents
* (typo) Update "Routines for updating validator status" in table of contents
* Update `FAR_FUTURE_SLOT` from `2**63` to `2**64 - 1`
* Put more constants in "Initial values", homogenise
* Cleanup note formatting
* Remove `ZERO_BALANCE_VALIDATOR_TTL` logic (to be possibly reintroduced in phase 2).
* Cleanup `min_empty_validator_index`
* Rename `deposit` to `amount` in `process_deposit` and `DepositData`.
* (typo) Remove new line under `process_penalties_and_exits`
* (typo) "Status codes" => "Status flags" in the table of contents
* (typo) `(state.slot - EPOCH_LENGTH) % LATEST_RANDAO_MIXES_LENGTH` => Use `SEED_LOOKAHEAD` instead.
* Put `state.validator_registry_latest_change_slot = state.slot` in `update_validator_registry`.
* Use `GENESIS_SLOT` for `last_poc_change_slot=0` and `second_last_poc_change_slot=0`.
Bugfixes
* (typo) `validator_exit` => `exit.validator_index`
* Separate initial deposits and initial activations to avoid double activations
* Replace `proposer.status != EXITED_WITH_PENALTY` with `validator.penalized_slot > state.slot` in two different places.
* Replace `status == EXITED_WITH_PENALTY` with `validator.penalized_slot <= state.slot` (and validator active) in two different places.
* Added `activation_slot`, `exit_slot`, `penalized_slot`, `withdrawal_slot`, use these to determine if a validator is active
* Universal min activation/exit delay of 256 slots
* Min exit time of ~1 day, but penalization delays this to ~18 days
* Penalty calculation period of `[time penalized - 18 days, time penalized + 18 days]`; made the total penalties array fixed size and wraparound to make calculation more fine-grained
* Processes withdrawals in all epochs, not just dynasty-changing epochs
* Change `get_shuffling` function to take slot as argument
Not yet done:
* Removed `shard_committees` from the state
* Removed persistent committees from the state
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...)
Removed the use of `clamp` from the spec, as there's no point in a helper function that's used exactly once; it only increases the amount people have to jump around the spec to understand what's going on.
Response to #295
Also a simplification, as two special cases get replaced: `state.randao_mix` -> `state.latest_randao_mixes[-1]`, and `state.next_seed` -> `state.latest_randao_mixes[-CYCLE_LENGTH-1]`.
Vitalik Buterin
Danny Ryan
Ben Edgington
terence tsao
Akhila Raju
Hsiao-Wei Wang
Alex Stokes
Justin
Nishant Das
Joseph Delong
Chih Cheng Liang
Anirudha Bose
Dan Burnett