diff --git a/documents/coredocument.go b/documents/coredocument.go
index 4cb5d120a..e32f57ef6 100644
--- a/documents/coredocument.go
+++ b/documents/coredocument.go
@@ -512,7 +512,13 @@ func generateTransitionRulesFingerprintHash(fingerprint coredocumentpb.Transitio
 		return nil, err
 	}
 
-	return sha3.NewLegacyKeccak256().Sum(fm), nil
+	s := sha3.NewLegacyKeccak256()
+	_, err = s.Write(fm)
+	if err != nil {
+		return nil, err
+	}
+
+	return s.Sum(nil), nil
 }
 
 // TODO remove as soon as we have a public method that retrieves the parent prefix