beacon: Use Blake2b Sum512 Instead of 256 (#419)

* Revert "Add Skip Coverage Condition in Coverage.sh (#416)"

This reverts commit 72a5dd1cf4.

* use blake2b512

* messed up on coverage.sh

beacon-chain/sync/service_test.go

@@ -132,7 +132,7 @@ func TestProcessBlockHash(t *testing.T) {
 		exitRoutine <- true
 	}()
 
-	announceHash := blake2b.Sum256([]byte{})
+	announceHash := blake2b.Sum512([]byte{})
 	hashAnnounce := &pb.BeaconBlockHashAnnounce{
 		Hash: announceHash[:],
 	}
@@ -329,7 +329,7 @@ func TestProcessCrystallizedHash(t *testing.T) {
 		exitRoutine <- true
 	}()
 
-	announceHash := blake2b.Sum256([]byte{})
+	announceHash := blake2b.Sum512([]byte{})
 	hashAnnounce := &pb.CrystallizedStateHashAnnounce{
 		Hash: announceHash[:],
 	}
@@ -362,7 +362,7 @@ func TestProcessActiveHash(t *testing.T) {
 		exitRoutine <- true
 	}()
 
-	announceHash := blake2b.Sum256([]byte{})
+	announceHash := blake2b.Sum512([]byte{})
 	hashAnnounce := &pb.ActiveStateHashAnnounce{
 		Hash: announceHash[:],
 	}
@@ -396,7 +396,7 @@ func TestProcessBadCrystallizedHash(t *testing.T) {
 	}()
 
 	// Send blockHashAnnounce msg format to crystallized state channel. Should fail
-	announceHash := blake2b.Sum256([]byte{})
+	announceHash := blake2b.Sum512([]byte{})
 	hashAnnounce := &pb.BeaconBlockHashAnnounce{
 		Hash: announceHash[:],
 	}
@@ -430,7 +430,7 @@ func TestProcessBadActiveHash(t *testing.T) {
 	}()
 
 	// Send blockHashAnnounce msg format to active state channel. Should fail
-	announceHash := blake2b.Sum256([]byte{})
+	announceHash := blake2b.Sum512([]byte{})
 	hashAnnounce := &pb.BeaconBlockHashAnnounce{
 		Hash: announceHash[:],
 	}

beacon-chain/types/block.go

@@ -69,7 +69,10 @@ func (b *Block) Hash() ([32]byte, error) {
 	if err != nil {
 		return [32]byte{}, fmt.Errorf("could not marshal block proto data: %v", err)
 	}
-	return blake2b.Sum256(data), nil
+	var hash [32]byte
+	h := blake2b.Sum512(data)
+	copy(hash[:], h[:32])
+	return hash, nil
 }
 
 // ParentHash corresponding to parent beacon block.

beacon-chain/types/state.go

@@ -94,7 +94,10 @@ func (a *ActiveState) Hash() ([32]byte, error) {
 	if err != nil {
 		return [32]byte{}, err
 	}
-	return blake2b.Sum256(data), nil
+	var hash [32]byte
+	h := blake2b.Sum512(data)
+	copy(hash[:], h[:32])
+	return hash, nil
 }
 
 // PendingAttestations returns attestations that have not yet been processed.
@@ -150,7 +153,10 @@ func (c *CrystallizedState) Hash() ([32]byte, error) {
 	if err != nil {
 		return [32]byte{}, err
 	}
-	return blake2b.Sum256(data), nil
+	var hash [32]byte
+	h := blake2b.Sum512(data)
+	copy(hash[:], h[:32])
+	return hash, nil
 }
 
 // LastStateRecalc returns when the last time crystallized state recalculated.

beacon-chain/utils/shuffle.go

@@ -16,7 +16,7 @@ func ShuffleIndices(seed common.Hash, validatorList []int) ([]int, error) {
 		return nil, errors.New("Validator count has exceeded MaxValidator Count")
 	}
 
-	hashSeed := blake2b.Sum256(seed[:])
+	hashSeed := blake2b.Sum512(seed[:])
 	validatorCount := len(validatorList)
 
 	// shuffle stops at the second to last index.

client/beacon/service.go

@@ -136,7 +136,10 @@ func (s *Service) fetchCrystallizedState(client pb.BeaconServiceClient) {
 			log.Errorf("Could not marshal crystallized state proto: %v", err)
 			continue
 		}
-		crystallizedStateHash := blake2b.Sum256(stateData)
+		var crystallizedStateHash [32]byte
+		h := blake2b.Sum512(stateData)
+		copy(crystallizedStateHash[:], h[:32])
+
 		dynasty := crystallizedState.GetCurrentDynasty()
 
 		for i, validator := range crystallizedState.GetValidators() {