diff --git a/consensus/consensus.go b/consensus/consensus.go
index 1e013d5d4c..87228ae49d 100644
--- a/consensus/consensus.go
+++ b/consensus/consensus.go
@@ -120,3 +120,14 @@ type PoW interface {
 	// Hashrate returns the current mining hashrate of a PoW consensus engine.
 	Hashrate() float64
 }
+
+// Istanbul is a consensus engine to avoid byzantine failure
+type Istanbul interface {
+	Engine
+
+	// Start starts the engine
+	Start(chain ChainReader, currentBlock func() *types.Block, hasBadBlock func(hash common.Hash) bool) error
+
+	// Stop stops the engine
+	Stop() error
+}