1. Chapter 8 Safeguarding the Internet

2. Firewalls Firewalls: hardware & software that are built using routers, servers and other software A point between a corporate network and the Internet System administrator Packet filtering: a screening router examines the header of every packet of data traveling Router could block any traffic Proxy Server: server software that runs on a host in a firewall A request from the corporate network’s computer is sent to the proxy server, which contacts the server on the Internet, and then sends the information from the net server to the computer

3. Viruses Malicious programs Cause different kinds of damages: deleting files, removing programs Computer (PC or Macintosh) can infected by viruses from: networks, e-mails, removable storage Viruses attach themselves to four parts: 1) Program files 2) File-directory system 3) Boot and system areas 4) Data files Trojan horses, Worms Anti-Virus Software (Eradication Program): System scanning

4. Cookies & Tracking Work Cookies: bits of data put on a hard disk when someone visits a web site Easier for people to use Web sites that require a user name and password Track how people use a Web site Users have the option of not allowing cookies to be placed on their hard disks (browsers option) Other methods: 1. Examine Web server logs in details 2. Using “sniffers” to examine every packet 3. helpful for Webmasters to create better sites

5. Cookies & Tracking Work OPS: Open Profiling Standard To allay people’s privacy concern, some organizations such as Microsoft & Netscape agreed on an “OPS” Give people much more control OPS is integrated into browsers

6. Cryptography and Privacy Internet will never be a secure place to do business or send private information Information needs to be encrypted & decrypted by “cryptosystems” Keys: secret values that computers use to encrypt and decrypt messages The idea is: if someone encrypts a message with a key, only someone else with matching key can decrypt the message

7. Cryptography and Privacy Encryption system’s kinds: 1) Secret-key cryptography “symmetric cryptography”: one secret key 2) Public-key cryptography “asymmetric cryptography”: two keys, public & private Data Encryption Standard (DES) is the most common secret-key cryptography system The best known public-key system is (RSA) A public-key system is useful for business on the Internet