prysm-pulse/beacon-chain/core/helpers/randao.go
shayzluf 59575bcac9
fuzz core/blocks package (#4907)
* fuzz core/blocks package

* gaz goimports

* fix test

* terence feedback

* terence feedback

* add error to domain. halfway through

* adding error to domain

* goimports

* added error handling to test

* error instead of continue

* terence and nishant feedback

* domain error handling

* domain error handling

* handle nil validator in ReadOnlyValidator creation

* goinmports

* [4]byte domain type

* [4]byte domain type

* [4]byte domain type fix tests

* fix tests

Co-authored-by: Raul Jordan <raul@prysmaticlabs.com>
Co-authored-by: terence tsao <terence@prysmaticlabs.com>
2020-03-03 19:02:14 +05:30

57 lines
1.9 KiB
Go

package helpers
import (
stateTrie "github.com/prysmaticlabs/prysm/beacon-chain/state"
"github.com/prysmaticlabs/prysm/shared/bls"
"github.com/prysmaticlabs/prysm/shared/bytesutil"
"github.com/prysmaticlabs/prysm/shared/hashutil"
"github.com/prysmaticlabs/prysm/shared/params"
)
// Seed returns the randao seed used for shuffling of a given epoch.
//
// Spec pseudocode definition:
// def get_seed(state: BeaconState, epoch: Epoch, domain_type: DomainType) -> Hash:
// """
// Return the seed at ``epoch``.
// """
// mix = get_randao_mix(state, Epoch(epoch + EPOCHS_PER_HISTORICAL_VECTOR - MIN_SEED_LOOKAHEAD - 1)) # Avoid underflow
// return hash(domain_type + int_to_bytes(epoch, length=8) + mix)
func Seed(state *stateTrie.BeaconState, epoch uint64, domain [bls.DomainByteLength]byte) ([32]byte, error) {
// See https://github.com/ethereum/eth2.0-specs/pull/1296 for
// rationale on why offset has to look down by 1.
lookAheadEpoch := epoch + params.BeaconConfig().EpochsPerHistoricalVector -
params.BeaconConfig().MinSeedLookahead - 1
randaoMix, err := RandaoMix(state, lookAheadEpoch)
if err != nil {
return [32]byte{}, err
}
seed := append(domain[:], bytesutil.Bytes8(epoch)...)
seed = append(seed, randaoMix...)
seed32 := hashutil.Hash(seed)
return seed32, 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: Epoch) -> Hash:
// """
// Return the randao mix at a recent ``epoch``.
// """
// return state.randao_mixes[epoch % EPOCHS_PER_HISTORICAL_VECTOR]
func RandaoMix(state *stateTrie.BeaconState, epoch uint64) ([]byte, error) {
currMix, err := state.RandaoMixAtIndex(epoch % params.BeaconConfig().EpochsPerHistoricalVector)
if err != nil {
return nil, err
}
newMixLength := len(currMix)
newMix := make([]byte, newMixLength)
copy(newMix, currMix)
return newMix, nil
}