New generation of safe messaging: “Letter Sealing” « LINE Engineers' Blog

The default encryption method used in LINE Any modern mobile messaging app or social networking service has servers that store and send message data. Servers decrypt messages or other data that are sent by users and then send them back to the recipient. If the server cannot immediately deliver the data to the recipient, the data will be temporarily stored while the recipient receives a push notification that lets them know there is a new message.