Many people have access to the network system, often from remote locations. However, to begin with, network operating systems provide basic security features, such as user dentiegbation and authentication, probably by password. Sophisticated network systems can permit network supervisors to assign varying access rights to individual users. All users, for example, could access word processing software, but only certain users could access payroll files. Some network software can limit how many times users can call up a particular file and generate an audit trial of who looked at which files. One fundamental approach to network security is to dedicate one network computer is accessible to people outside the network, and that one computer accepts only appropriate access. Among its other chores, a firewall computer can call back all remote-access terminals.
In addition to monitoring access to the network, organizations must be concerned about unauthorized people intercepting data in transit, possibly thieves or industrial spies. Data being sent over communication lines may be protected by scrambling the messages-that is, putting them in code that can be broken only by the person receiving the message. The process of scrambling messages is called encryption. The American National Standards Institute has endorsed a process called the data Encryption Standard (DES), a standardized public key by which senders and receivers can scramble and unscramble message. Although the DES code is well known, companies still use it because the method makes it quite expensive to intercept coded messages. Encryption software is available for personal computers. A typical package, for example, offers a variety of security features : file encryption, keyboard lock, and password protection.
In addition to monitoring access to the network, organizations must be concerned about unauthorized people intercepting data in transit, possibly thieves or industrial spies. Data being sent over communication lines may be protected by scrambling the messages-that is, putting them in code that can be broken only by the person receiving the message. The process of scrambling messages is called encryption. The American National Standards Institute has endorsed a process called the data Encryption Standard (DES), a standardized public key by which senders and receivers can scramble and unscramble message. Although the DES code is well known, companies still use it because the method makes it quite expensive to intercept coded messages. Encryption software is available for personal computers. A typical package, for example, offers a variety of security features : file encryption, keyboard lock, and password protection.
