HVAC Control in the New Millennium.pdf - HVAC.Amickracing

Computer Networks and Securitythey also lead to information theft or corruption. Network informationcan reside on a hard drive or be in transit across the network cable in theform of packets. Serious hackers are also called crackers. They maybecome active in accessing your network and should be considered athreat. Some of their methods create holes within the operating system,which allows easy access for hackers.Security TechnologyLevels of security should be implemented for Internet implementations.These will restrict the levels of access made available to remoteusers. This type of security is available from NT, Internet InformationServer (IIS) security, SSL (Secure Socket Layers), Digital Certificates andencryption.In Wonderware software there are three types of protected dataaccess via the Internet. These are:• Read-only access of SQL clients, which are ActiveX objects,• Read-only access of real-time process graphics using standard NTand IIS security,• Runtime, a module which gives remote users the ability to respondto emergencies, security for the user is predefined using NT andIIS security administration.In Windows NT-based systems, general security is supportedthrough the OS and IIS (Figure 7-4). Windows NT allows the user toenable and disable access to files and directories by user or group. WithIIS manager more security restricting read/write accesses can be added.Security technology includes SSL, Digital certificates and HTTPS.SSL is a protocol developed by Netscape that allows a secure transactionbetween standard browsers and Web servers on the Internet. Both theNetscape Navigator and Internet Explorer browsers support SSL.Encryption is another type of security. Data can be encrypted usinga secret key for encryption (symmetric) or public key encryption (asymmetric).In secret key encryption both parties share the same passwordor key. In public key encryption, there are two keys that are related, oneis private and the other public. SSL uses the public key method of encryption.©2001 by The Fairmont Press, Inc. All rights reserved.