diff --git a/common/types.go b/common/types.go
index 12c26d94bc..e599bce1e9 100644
--- a/common/types.go
+++ b/common/types.go
@@ -30,7 +30,9 @@ import (
 )
 
 const (
-	HashLength    = 32
+	// HashLength is the expected length of the hash
+	HashLength = 32
+	// AddressLength is the expected length of the adddress
 	AddressLength = 20
 )