Unit8（课件）-《电子商务英语》同步教学（大连理工大学出版社）

Learning Objectives Upon completion of this chapter, you will be able to: ● know the security plan for e-business; ● understand the features of SET; ● know how to assure Internet security in China. Unit 8 E-commerce Security Passage A Erect Firewalls 8.1 　　A firewall is a set of related programs, located at a network gateway server that protects the resources of a private network from users of other networks. A company with an intranet that allows its workers to have access to the wider Internet installs a firewall to prevent outsiders from accessing its own private data resources and for controlling what outside resources its own users have access to. Basically, a firewall, working closely with a router program, examines each network packet to determine whether to forward it toward its destination. A firewall also includes or works with a proxy server that makes network requests on behalf of workstation users. A firewall is often installed in a specially designated computer separate from the rest of the network so that no incoming request can get directly at private network resources. Passage A Employ Encryption Methods 8.2 　　Encryption is the process of scrambling information into an unreadable form. Companies can safeguard information from outsiders by encrypting that data before transmitting it over the Internet. For example, the plain test message “Meet me at 2 p.m.”is encrypted using a cipher that will add a specific number of characters to each letter. The key is the exact number that will be added. If the key is 3, the resulting cipher text is “Phhw ph dw 5 s.p.”. 　　An effective encryption method requires two keys—one key is used to encrypt the message from plain text into cipher text (called public key), and the other key is used to decrypt the message from cipher text into plain text (called private key). If two different keys are used, the encryption system is referred to as “asymmetric encryption”. When both keys are the same, the system is referre