diff --git a/const.go b/const.go
index cee1d94..6f45fa3 100644
--- a/const.go
+++ b/const.go
@@ -14,3 +14,4 @@ const defaultCookieLen uint32 = 32
 // If set the cookie expiration when the browser is closed (-1), set the expiration as a keep alive (2 days)
 // so as not to keep dead sessions for a long time
 const keepAliveExpiration = 2 * 24 * time.Hour
+const expirationAttrKey = "__store:expiration__"
diff --git a/store.go b/store.go
index eab11a8..6c38d7a 100644
--- a/store.go
+++ b/store.go
@@ -1,14 +1,9 @@
 package session
 
 import (
-	"fmt"
 	"time"
-
-	"github.com/savsgio/gotils/bytes"
 )
 
-var expirationAttrKey = fmt.Sprintf("__store:expiration:%s__", bytes.Rand(make([]byte, 5)))
-
 // NewStore returns a new empty store
 func NewStore() *Store {
 	return &Store{