dione/consensus/randomness.go

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package consensus
import (
"encoding/binary"
"github.com/Secured-Finance/dione/types"
"github.com/filecoin-project/go-state-types/crypto"
"github.com/minio/blake2b-simd"
"golang.org/x/xerrors"
)
func DrawRandomness(rbase []byte, pers crypto.DomainSeparationTag, round types.DrandRound, entropy []byte) ([]byte, error) {
h := blake2b.New256()
if err := binary.Write(h, binary.BigEndian, int64(pers)); err != nil {
return nil, xerrors.Errorf("deriving randomness: %w", err)
}
VRFDigest := blake2b.Sum256(rbase)
_, err := h.Write(VRFDigest[:])
if err != nil {
return nil, xerrors.Errorf("hashing VRFDigest: %w", err)
}
if err := binary.Write(h, binary.BigEndian, round); err != nil {
return nil, xerrors.Errorf("deriving randomness: %w", err)
}
_, err = h.Write(entropy)
if err != nil {
return nil, xerrors.Errorf("hashing entropy: %w", err)
}
return h.Sum(nil), nil
}