Protection of the access to computer. Passwords are used to prevent unauthorized access to the data on the PC. PC allows the access to its resources only to the users who are registered and have entered the right password. Each user can be admitted only to peculiar information resources. At the same time all attempts of unauthorized access can be registered.

Nowadays biometric systems of authorization and identification are used to protect the PC from an unauthorized access. The characteristics used in them are an indispensable part of the person and can't be lost or feigned. Among biometric systems are a speech recognition system, a identification system using fingermarks and retinal scan.

Disc data protection. Each disc, folder or file of a local PC and a PC connected to a local system can be protected from unauthorized access. They can be attributed special access permissions (full access, read-only, password protection), and these permissions can differ within the users.

RAID (Redantant Arrays of Independent Disks) are used to provide more safety of filing on hard discs. Several hard discs can be connected to a special RAID-controller which concerns them as a whole logical medium. While logging the data is doubled and saved on several discs simultaneously, that's why if one of the discs becomes faulty the data are not lost.

Information protection in the Internet. If a PC is connected to the Internet any user, who also has Internet access, can gain an access to informational resources of this PC. the mechanism of the entry from Internet into a local PC and a local network are different:

• Web-pages opened in the browser can contain active elements ActiveX or Java-applets that can destroy the data on the local PC;


• Some Web-servers set text-files cookie in the local PC, which can be used to get confidential information about its user.

To avoid it a special program or hardware barrier between the Internet and Intranet is installed. It's achieved due to firewall. It controls data communication between the networks, controls current connections, detects suspicious actions and thus prevents unauthorized access from the Internet into the local network.