Mobile phone short message confidentiality

Hello, landlord, to set the SMS security mode, you can find the security settings in the settings of your mobile phone, and then use a "private encryption" to open it. After you click on it, enter your mobile phone password, then enter the password you want to set, and then enter the private encryption to set it. Generally, there are phone books, short messages, call records and so on. This can be kept secret. Hope to adopt.

thank