gost34112012256/esptree.go | 2 +-

diff --git a/gost34112012256/esptree.go b/gost34112012256/esptree.go
index c3834bdfacc48ea214dbc54825c071fd5c71dca8bdbf6ec8fb22652efd833f3f..3a21229d4a84c041e9a67da35eb4998529432cff6f5f96fd636d8d038be6cd57 100644
--- a/gost34112012256/esptree.go
+++ b/gost34112012256/esptree.go
@@ -32,7 +32,7 @@ 	t := &ESPTree{
 		keyRoot: key,
 		key:     make([]byte, Size),
 	}
-	t.isPrev[0] += 1 // invalidate cache
+	t.isPrev[0]++ // invalidate cache
 	t.DeriveCached([]byte{0x00, 0x00, 0x00, 0x00, 0x00})
 	return t
 }