diff --git a/session/common.go b/session/common.go
index 957f44f..745d979 100644
--- a/session/common.go
+++ b/session/common.go
@@ -24,12 +24,14 @@ type Authorization struct {
 }
 
 func (auth *Authorization) ToStrings() []string {
+	ct, _ := auth.CreatedTime.MarshalJSON()
 	return []string{
 		"a", auth.Account.Hex(),
 		"p", auth.Platform,
 		"u", auth.Uid,
 		"al", auth.Alias,
 		"inv", auth.invalidated,
+		"ct", string(ct),
 	}
 }
 
@@ -39,12 +41,15 @@ func (auth *Authorization) Valid() bool {
 
 func MakeAuthrizationFromStringMap(src map[string]string) Authorization {
 	accid, _ := primitive.ObjectIDFromHex(src["a"])
+	var datetime primitive.DateTime
+	datetime.UnmarshalJSON([]byte(src["ct"]))
 	return Authorization{
 		Account:     accid,
 		Platform:    src["p"],
 		Uid:         src["u"],
 		Alias:       src["al"],
 		invalidated: src["inv"],
+		CreatedTime: datetime,
 	}
 }