storage/interface.go | 10 ++++++++--
 torrent.go           | 12 +++++++++++-

diff --git a/storage/interface.go b/storage/interface.go
index 869556f80a547265fad99ba61d919f77e57e59c1..584338cb4ae178d30ab1c04ee138981cb41f7071 100644
--- a/storage/interface.go
+++ b/storage/interface.go
@@ -22,8 +22,9 @@ 	Piece(metainfo.Piece) PieceImpl
 	Close() error
 }
 
-// Interacts with torrent piece data. Optional interfaces to implement include io.WriterTo, such as
-// when a piece supports a more efficient way to write out incomplete chunks
+// Interacts with torrent piece data. Optional interfaces to implement include:
+//   io.WriterTo, such as when a piece supports a more efficient way to write out incomplete chunks.
+//   SelfHashing, such as when a piece supports a more efficient way to hash its contents.
 type PieceImpl interface {
 	// These interfaces are not as strict as normally required. They can
 	// assume that the parameters are appropriate for the dimensions of the
@@ -43,3 +44,8 @@ type Completion struct {
 	Complete bool
 	Ok       bool
 }
+
+// Allows a storage backend to override hashing (i.e. if it can do it more efficiently than the torrent client can)
+type SelfHashing interface {
+	SelfHash() (metainfo.Hash, error)
+}
diff --git a/torrent.go b/torrent.go
index e38764742499d9db8fcd4b58b898cc9626d848aa..82b70c132cff0b25b58b10f3edc893d750d48b72 100644
--- a/torrent.go
+++ b/torrent.go
@@ -810,10 +810,20 @@ 	return pp.Integer(t.info.PieceLength)
 }
 
 func (t *Torrent) hashPiece(piece pieceIndex) (ret metainfo.Hash, err error) {
-	hash := pieceHash.New()
 	p := t.piece(piece)
 	p.waitNoPendingWrites()
 	storagePiece := t.pieces[piece].Storage()
+
+	//Does the backend want to do its own hashing?
+	if i, ok := storagePiece.PieceImpl.(storage.SelfHashing); ok {
+		var sum metainfo.Hash
+		//log.Printf("A piece decided to self-hash: %d", piece)
+		sum, err = i.SelfHash()
+		missinggo.CopyExact(&ret, sum)
+		return
+	}
+
+	hash := pieceHash.New()
 	const logPieceContents = false
 	if logPieceContents {
 		var examineBuf bytes.Buffer