Tip: To lock the device manually, press thepower key. A list of commands opens. SelectLock phone.● Lock if SIM card changed — You can set the deviceto ask for the lock code when an unknown SIM cardis inserted into your device. The device maintains alist of SIM cards that are recognized as the owner’scards.● Closed user group — You can specify a group ofpeople to whom you can call and who can call you(network service).● Confirm SIM services — You can set the device todisplay confirmation messages when you are usinga SIM card service (network service).Certificate managementSelect Menu > Tools > Settings and General >Security > Certificate management.Digital certificates do not guarantee safety; they areused to verify the origin of software.In the certificate management main view, you can seea list of authority certificates that are stored in yourdevice. Scroll right to see a list of personal certificates,if available.Digital certificates should be used if you want toconnect to an online bank or another site or remoteserver for actions that involve transferring confidentialinformation. They should also be used if you want toreduce the risk of viruses or other malicious softwareand be sure of the authenticity of software whendownloading and installing software.Important: Even if the use of certificates makesthe risks involved in remote connections and softwareinstallation considerably smaller, they must be usedcorrectly in order to benefit from increased security.The existence of a certificate does not offer anyprotection by itself; the certificate manager mustcontain correct, authentic, or trusted certificates forincreased security to be available. Certificates have arestricted lifetime. If "Expired certificate" or"Certificate not valid yet" is shown, even if thecertificate should be valid, check that the current dateand time in your device are correct.View certificate details—check authenticityYou can only be sure of the correct identity of a serverwhen the signature and the validity period of a servercertificate have been checked.You are notified if the identity of the server is notauthentic or if you do not have the correct securitycertificate in your device.To check certificate details, scroll to a certificate, andselect Options > Certificate details. The validity ofthe certificate is checked, and one of the followingnotes may be displayed:● Certificate not trusted — You have not set anyapplication to use the certificate.146 Settings
