92 Copyright © 2004 Nokia
• CACHE MEMORY
The information or services you have accessed are stored in the cache of your phone.
A cache is a buffer memory that stores data temporarily.
To empty the cache while browsing, select Options > Other options > Clear the cache.
To empty the cache in the standby mode, select Menu > Services > Clear the cache.
• BROWSER SECURITY
Security features may be required for some services, such as banking services or shopping
on a site. For such connections you need security certificates and possibly a security module,
which may be available on your SIM card. For more information, contact your service provider.
CERTIFICATES
There are three kinds of certificates: server certificates, authority certificates, and
user certificates.
• Server certificates are used to improve security in connections between the phone and
the gateway. The phone receives the server certificate from the service provider before
the connection is established and its validity is checked using the authority certificates
that are saved on the phone. Server certificates are not saved.
The security icon is displayed during a connection if the data transmission between
the phone and the gateway (identified by the IP address in the Edit active service
settings) is encrypted.
However, the security icon is not an indication that the data transmission between the
gateway and the content server (place where the requested resource is saved) is secure.
It is up to the service provider to secure the data transmission between the gateway
and the content server.
• Authority certificates are used by some services, such as banking, for checking the
validity of other certificates. Authority certificates can be either saved in the security
module by the service provider, or they can be downloaded from the network, if the
service supports the use of authority certificates.
• User certificates are issued to users by a Certifying Authority. User certificates are
required, for example, to create a digital signature and they associate the user with a
specific private key in a security module.
While the use of certificates makes the risks involved in remote connections and software
installation considerably smaller, they must be used correctly in order to benefit from
increased security. The existence of a certificate does not offer any protection by itself. The
certificate manager must contain correct, authentic, or trusted certificates for increased
security to be available.
Certificates have a restricted lifetime. If Expired certificate or Certificate not valid yet is
shown (even if the certificate should be valid), check that the current date and time in your
phone are correct.