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# 7.2.3 Security: are my credit card details safe?

Many people now shop regularly on the web. However, many others don’t because they fear that an unscrupulous person could obtain their credit card details. They also fear that if they provide their names and addresses to a firm on the internet, they will be bombarded with junk mail (or its electronic equivalent, junk email). Some worry that since anyone can put up a website, the seller may be bogus, and no goods will appear after the sale has been completed, or they won’t be as advertised.

Consequently, this raises the important issues of security and trustworthiness. The internet is a remarkably open medium. It does not take too much effort to ‘capture’ the data that flows along communication lines. Someone could theoretically read your credit card details as they are transmitted between your computer and that of the seller. (‘Theoretically’ is used there because techniques exist which enable the data to be transformed into a form which would be virtually impossible to read.)

You can be reasonably confident of buying from a website if it displays one of two things.

1. The address shown in the bar at the top of the screen should start with ‘https’ instead of ‘http’. The letter ‘s’ means you are connected to a secure web server using techniques to protect your details from electronic snoopers.
2. An icon representing a small padlock/key is present. This also indicates that the web server you are connected to is a secure one.

Another safety precaution is to deal only with web sellers you know are reputable. Consumer organisations often have schemes for accrediting web sellers who are legitimate and secure dealers. Friends and neighbours may also be able to recommend reputable and secure web sellers.

## Activity 23 A distributed system

Allow about 5 minutes

Is web selling an example of a distributed system? Explain your reasoning.

(A text entry box would appear here, but your browser does not support it.)

### Discussion

Yes, it is a distributed system. It consists of user PCs, web servers, and database servers, with data and information being transferred between them using networks (in this case the internet).

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OpenLearn - An introduction to data and information in health and social care
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