A01 chaf6542 06 se fm indd

Virtual private 

network (VPN)

Private network created 

using the public network 

infrastructure of the 

Internet.

Secure Sockets 

Layer (SSL)

A commonly used 

encryption technique 

for scrambling data 

as it is passed across 

the Internet from a 

customer’s web browser 

to a merchant’s web 

server.

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Chapter 11  Analysis and design

When a customer enters a secure checkout area of an e-commerce site SSL is used and 

the customer is prompted that ‘you are about to view information over a secure connection’ 

and a key symbol is used to denote this security. When encryption is occurring they will see 

that the web address prefix in the browser changes from ‘http://’ to ‘https://’ and a padlock 

appears at the bottom of the browser window.

The main facilities it provides are security and confidentiality. SSL enables a private link 

to be set up between customer and merchant. Encryption is used to scramble the details 

of an e-commerce transaction as it is passed between sender and receiver and also when 

the details are held on the computers at each end. It would require a determined attempt 

to intercept such a message and decrypt it. SSL is more widely used than the rival S-HTTP 

method. Since, with enough computing power, time and motivation, it is possible to decrypt 

messages encrypted using SSL, much effort is being put into finding more secure methods 

of encryption such as 

SET

. From a merchant’s point of view there is also the problem that 

authentication of the customer is not possible without resorting to other methods such as 

credit checks.