dione/beacon/utils.go

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package beacon
import (
"encoding/binary"
"github.com/minio/blake2b-simd"
"golang.org/x/xerrors"
)
func DrawRandomness(rbase []byte, randomnessType RandomnessType, round uint64, entropy []byte) ([]byte, error) {
h := blake2b.New256()
if err := binary.Write(h, binary.BigEndian, int64(randomnessType)); err != nil {
return nil, xerrors.Errorf("deriving randomness: %v", 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: %v", err)
}
_, err = h.Write(entropy)
if err != nil {
return nil, xerrors.Errorf("hashing entropy: %v", err)
}
return h.Sum(nil), nil
}