prysm-pulse/beacon-chain/core/helpers/randao.go
terence tsao 8c04ced1a6 Name Changes to Align with V0.3 (#1621)
* fixed epoch_processing

* penalize->slash

* exit -> voluntary_exit

*  SEED_LOOKAHEAD -> MIN_SEED_LOOKAHED

* ENTRY_EXIT_DELAY -> ACTIVATION_EXIT_DELAY

* `INCLUDER_REWARD_QUOTIENT` -> `ATTESTATION_INCLUSION_REWARD_QUOTIEN`

* LatestIndexRoots -> LatestActiveIndexRoots

* `MIN_VALIDATOR_WITHDRAWAL_EPOCHS` -> `MIN_VALIDATOR_WITHDRAWAL_DELAY`

* MAX_WITHDRAWALS_PER_EPOCH -> MAX_EXIT_DEQUEUES_PER_EPOCH

* ETH1_DATA_VOTING_PERIOD -> EPOCHS_PER_ETH1_VOTING_PERIOD

* SLOT_DURATION -> SECONDS_PER_SLOT

* EPOCH_LENGTH -> SLOTS_PER_EPOCH

* SLOT_DURATION -> SECONDS_PER_SLOT take 2

* rest of the misc fixes for config name changes

* remove tools/bootnode/.!74296!bootnode.go

* `current_epoch_start_shard` -> `current_shuffling_start_shard`, `current_shuffling_epoch`, `current_shuffling_see`

* go fmt

* fixed comment

* updated pseudocode comments

* merged master
2019-02-18 10:52:16 -06:00

84 lines
3.2 KiB
Go

package helpers
import (
"fmt"
pb "github.com/prysmaticlabs/prysm/proto/beacon/p2p/v1"
"github.com/prysmaticlabs/prysm/shared/hashutil"
"github.com/prysmaticlabs/prysm/shared/params"
)
// GenerateSeed generates the randao seed of a given epoch.
//
// Spec pseudocode definition:
// def generate_seed(state: BeaconState,
// epoch: EpochNumber) -> Bytes32:
// """
// Generate a seed for the given ``epoch``.
// """
// return hash(
// get_randao_mix(state, epoch - MIN_SEED_LOOKAHED) +
// get_active_index_root(state, epoch)
// )
func GenerateSeed(state *pb.BeaconState, wantedEpoch uint64) ([32]byte, error) {
if wantedEpoch > params.BeaconConfig().MinSeedLookahead {
wantedEpoch -= params.BeaconConfig().MinSeedLookahead
}
randaoMix, err := RandaoMix(state, wantedEpoch)
if err != nil {
return [32]byte{}, err
}
indexRoot, err := ActiveIndexRoot(state, wantedEpoch)
if err != nil {
return [32]byte{}, err
}
return hashutil.Hash(append(randaoMix, indexRoot...)), nil
}
// ActiveIndexRoot returns the index root of a given epoch.
//
// Spec pseudocode definition:
// def get_active_index_root(state: BeaconState,
// epoch: EpochNumber) -> Bytes32:
// """
// Return the index root at a recent ``epoch``.
// """
// assert get_current_epoch(state) - LATEST_INDEX_ROOTS_LENGTH + ACTIVATION_EXIT_DELAY < epoch <= get_current_epoch(state) + ENTRY_EXIT_DELAY
// return state.latest_index_roots[epoch % LATEST_INDEX_ROOTS_LENGTH]
func ActiveIndexRoot(state *pb.BeaconState, wantedEpoch uint64) ([]byte, error) {
var earliestEpoch uint64
currentEpoch := CurrentEpoch(state)
if currentEpoch > params.BeaconConfig().LatestActiveIndexRootsLength+params.BeaconConfig().ActivationExitDelay {
earliestEpoch = currentEpoch - (params.BeaconConfig().LatestActiveIndexRootsLength + params.BeaconConfig().ActivationExitDelay)
}
if earliestEpoch > wantedEpoch || wantedEpoch > currentEpoch {
return nil, fmt.Errorf("input indexRoot epoch %d out of bounds: %d <= epoch < %d",
wantedEpoch, earliestEpoch, currentEpoch)
}
return state.LatestIndexRootHash32S[wantedEpoch%params.BeaconConfig().LatestActiveIndexRootsLength], nil
}
// RandaoMix returns the randao mix (xor'ed seed)
// of a given slot. It is used to shuffle validators.
//
// Spec pseudocode definition:
// def get_randao_mix(state: BeaconState,
// epoch: EpochNumber) -> Bytes32:
// """
// Return the randao mix at a recent ``epoch``.
// """
// assert get_current_epoch(state) - LATEST_RANDAO_MIXES_LENGTH < epoch <= get_current_epoch(state)
// return state.latest_randao_mixes[epoch % LATEST_RANDAO_MIXES_LENGTH]
func RandaoMix(state *pb.BeaconState, wantedEpoch uint64) ([]byte, error) {
var earliestEpoch uint64
currentEpoch := CurrentEpoch(state)
if currentEpoch > params.BeaconConfig().LatestRandaoMixesLength {
earliestEpoch = currentEpoch - params.BeaconConfig().LatestRandaoMixesLength
}
if earliestEpoch > wantedEpoch || wantedEpoch > currentEpoch {
return nil, fmt.Errorf("input randaoMix epoch %d out of bounds: %d <= epoch < %d",
wantedEpoch, earliestEpoch, currentEpoch)
}
return state.LatestRandaoMixesHash32S[wantedEpoch%params.BeaconConfig().LatestRandaoMixesLength], nil
}