* Address the slot/epoch underflow problem, even for Java implementers! 🎉
* Squash a bug with `get_previous_epoch`
* Fix#642
* Address #626 (Vitalik, Danny, myself agree that avoiding signed integers is probably best)
* Updated phase 1: branch challenges
* Removed unnecessary line
* Added early subkey reveal slashing
* Revealing during the active period is still revealing early
* Added....
* Machinery for publishing old subkeys
* Inability to withdraw until you published all subkeys
* After a validator exits the queue there's still a minimum 1-day delay before they can withdraw (in the future this delay will be used as an opportunity to start a PoC challenge game)
* Update 1_shard-data-chains.md
* formatting
* minor edits
* Added masking scheme for reveals
Secure under the aggregate extraction infeasibility assumption described on pages 11-12 of https://crypto.stanford.edu/~dabo/pubs/papers/aggreg.pdf
* Added rewards going to challengers
* Add ToC and reorg the constant tables
* Remove tags
* fix constant formatting
* normalize domain constants in phase 1
* Update 1_shard-data-chains.md
* Update 1_shard-data-chains.md
* Update 1_shard-data-chains.md
* Added transition logic
* Fix ToC
* Fix ToC
* Adjusted for #615
* Added more helpers
* epoch -> slot
* fix some type hints
* clean up `get_attestation_merkle_depth`
This function is used to get the merkle root of some block roots which are themselves hashes, so the leaves do not need to be rehashed.
Unfortunately, it's easy to assume that a merkle_root function would hash its leaves, so it should be clarified.
* Bring forward changes to withdrawability from phase 1
* The `WITHDRAWABLE` flag is removed; instead, a validator's withdrawability is determined through the `withdrawable_epoch` field (renamed and re-purposed from `withdrawal_epoch` which was not used)
* When a validator passes through the withdrawal queue, the `prepare_validator_for_withdrawal` function does not let them withdraw immediately; instead, they have to wait `MIN_VALIDATOR_WITHDRAWAL_EPOCHS`. This extra minimum delay serves no value in phase 0, but is crucial for phase 1 as the period between a validator passing through the queue and the validator being eligible to withdraw is where proof of custody challenges can come in; adding it in phase 0 is only half a line of code so easier to add it now.
* If a validator is penalized, they are no longer subject to the exit queue; instead, their `withdrawable_epoch` is set `LATEST_PENALIZED_EXIT_LENGTH` into the future and this is used to determine when the validator can withdraw
* Changes the eligibility condition for a transfer to use the `withdrawable_epoch`
1. Use `+` to concatenate the merkle roots in `hash` function.
2. Fix `pad_to_power_of_2`: padding with `[b'\x00' * SHARD_BLOCK_SIZE]`,
not `[SHARD_BLOCK_SIZE]`.
Adds the crosslink committee to the fork choice rule. This is useful because it means that even if a proposal committee is byzantine and attempts to prevent a crosslink via a "balance attack" (alternating between chain A and chain B being the canonical chain), the crosslink committee can force the equilibrium to flip to one side or the other.
The reason to do this is that it makes it calculable from inside an attestation how many epochs the attestation spans over, which is needed for proof of custody reasons. It's a relatively small change and so arguably easier to do now than to do as a patch in phase 1.
Note that this changes the meaning of latest_crosslink.epoch, from the epoch when the latest crosslink was included to the epoch that the latest crosslink was for. This affects the line:
* `state.latest_crosslinks[shard].epoch > state.validator_registry_update_epoch` for every shard number `shard` in `[(state.current_epoch_start_shard + i) % SHARD_COUNT for i in range(get_current_epoch_committee_count(state))]` (that is, for every shard in the current committees)
But this may actually make it _more_ correct, as it means that in the case where >512 shards are processed per epoch, and so a committee from the previous epoch could get finalized in the current epoch, that would no longer count toward every shard having received a "new" crosslink.
Hsiao-Wei Wang
Justin
vbuterin
Alex Stokes
terence tsao
Danny Ryan
Cayman
d-yokoi
d-yokoi
Paul Hauner
Jonny Rhea
Jacek Sieka
Dean Eigenmann
Anton Nashatyrev