Nokia 6170 User Guide 85 Copyright © 2004 NokiaMobile Internet servicesChange module PIN—Change the module PIN, if allowed by the security module.Change signing PIN—Select and change a signing PIN.Digital signatureYou can make digital signatures with your phone if your SIM card has a securitymodule. The signature can be traced back to you through the private key on thesecurity module and the user certificate that was used to perform the signature.Using the digital signature can be the same as signing your name to a paperbill, contract, or other document.1 While browsing, select a link on a page, such as the title of the book youwant to buy and its price.The text to sign (possibly including amount, date, etc.) is shown.2 Check that the header text is Read and that the digital signature iconis shown.If the digital signature icon does not appear, there is a security breach. Donot enter any personal data such as your signing PIN.3 Scroll through and read all of the text before signing.4 To sign the text, select Sign.5 Select the user certificate you want to use, enter the signing PIN (providedwith the SIM card if the SIM card has a security module), and select OK.The digital signature icon disappears, and the service may display aconfirmation of your purchase.Cache memoryThe information or services you access with the browser are temporarily saved inthe cache memory of the phone.If you tried to access or have accessed confidential information requiringpasswords (for example, your bank account), clear the cache after each use.To clear the cache from the menu, select Web > Clear the cache.To clear the cache while browsing, select Options > Other options >Clear the cache.CertificatesThere are three kinds of certificates: server, authority, and user.Certificates have a restricted lifetime. If Expired certificate or Certificate notvalid yet is shown even though the certificate should be valid, check that thecurrent date and time settings in your phone are correct. Before changing thesesettings, make sure that you really trust the owner of the certificate and thatthe certificate really belongs to the listed owner.
