Wolmer’s High School for Girls
Information Technology
Form: 5
Lesson Notes: Protecting and Securing Information
Numerous methods are used to protect and secure information. The most widely used of these are:
· Passwords
· File encryption
· Physical access restriction
· Software access restriction
· Firewalls
· Back-up and recovery
· Fireproof cabinets
· Archiving
· Virus protection
Passwords
A password is a combination of characters used to prevent unauthorised computer access. A person wishing to secure a computer or individual files on the computer can set a password. In order for access to be granted, the correct password must be entered.
Encryption
Encryption is the process of encoding information so that it bears no similarity to the original in order to secure it. Files are encrypted using a key provided by the person who wants to encrypt the information. This key is a combination of characters that is used to tell an encoding algorithm how to encrypt the information.
This is the process of decoding encrypted information in order to obtain the original information. A key is required to do so, the same key that was used to encrypt the information. If the wrong is entered, the file (s) cannot be decrypted.
Physical access restriction
Physical access restrictions are used to prevent unauthorised persons from gaining physical access to stored information. Two methods of physical access restriction are:
· Housing the computer or the removable storage in a room or building. This area would be secured using locks and a combination of surveillance cameras, alarms and security guards
· Locking manual files or removable storage in a cabinet or vault
Software access restriction
This is the process of restricting access to software; this may be done using passwords or encryption.
Virus
A virus is a malicious program that is designed to corrupt the files on a person’s computer and/or prevent the computer from working properly. A computer virus will spread from one infected file or computer to another. Viruses may cause damage to programs and data. The way this damage is done and the method of transmission depends on the virus. People create viruses for electronic vandalism, revenge or mischief. Computers may be protected from viruses by avoiding using computers or disks that are suspected of having a virus by using up-to-date anti-virus software.
E-mail viruses
An increasing number of viruses are being spread by the attachments to e-mail messages. When you open the attachment your computer becomes infected. Some of these viruses can even take advantage of the capabilities of e-mail and send themselves to everyone in an e-mail address book.
Anti-virus software
An anti-virus or virus guard is a special type of software that tries to detect and remove viruses that are on a computer or removable storage media. New viruses come out every day, so virus-guards need to be kept up to date. Many anti-virus programs allow you to download new virus definitions (information about how to recognise particular viruses). Advanced anti-virus programs, such as Norton Anti-virus, also try to detect viruses for which there aren’t yet virus definitions by observing programs for suspicious, virus-like activity.
Fireproof cabinets
A fireproof cabinet is a cabinet that is designed to withstand the high temperatures of a fire. When things that would ordinarily burn (or melt) very easily, e.g. paper or disks, are placed inside one of these, they are also protected from fire.
Firewalls
A firewall is a program that identifies certain weaknesses in networked computers and tries to prevent them from being exploited. This makes it much more difficult (but not impossible) for hackers to gain unauthorised access to the computer. Therefore firewalls help to keep the data on these computers secure. Firewalls are often installed on computers that access the internet, especially those that have a permanent connection through cable modems and DSL. Since computers that use dial-up connections are not always connected to the internet, hackers do not target them as often.
Computer Hackers
A hacker is a person who tries to gain access to areas on networks that he/she is not supposed to have access to. Hackers may try to:
· Pretend to be someone who has legitimate access to certain areas or files
· Use brute force attacks (trying thousands of passwords until the right is found)
· Find weaknesses in the network (known as backdoors) and try to exploit them
· Put Trojan horses on computers in the network so that they can gain easy access to restricted areas
· Corrupt or delete the files being shared
Back-up and Recovery
Backing data is the process of making a copy of the data and storing it on another storage medium. The storage media most commonly used for this process are: CD-RW, magnetic tape, diskettes and zip disks (disks that are roughly the size of a floppy disk but have a capacity of around 250mb).
If the original data is lost, misplaced or destroyed, it can be recovered by copying the back-up onto the computer. Data should be backed-up on a regular basis and should be placed in a fireproof cabinet and/or a copy should be kept at a different site.
Archiving
When data has remained unchanged for a long time and is not accessed on a regular basis, it is said to be inactive. This data is taking up valuable space, you might want to store it in a separate location instead. This is what is known as archiving. This also refers to when a second back-up of a file is kept separately from the working back-up copy.
Data corruption
When something causes data to become lost or damaged, this data is said to be corrupted. Data can be corrupted by:
· A computer virus
· Wilful acts of employees
· Computer malfunction
· Power surges or outages
· Poor methods for updating data
Ways to reduce the risk of corruption:
· Minimising the risk of computer malfunction by performing periodic computer maintenance and keeping the computer in a cool room away from smoke and dust
· Using surge protectors and uninterrupted power supply units
· Performing quality control audits to minimise wilful corruption
· Installing anti-virus software
1. State two ways in which data is corrupted and explain how each can be avoided
2. Identify five measures that can be taken to secure data
3. Answer the following questions:
(a) What is encryption?
(b) What is decrypting as it relates to encryption?
4. Answer the following questions:\
(a) What is a virus?
(b) How can viruses be avoided?
(c) Name two types of anti-virus software
5. In order to secure its data, a company uses the following method for encrypting text:
A letter is replaced by the letter five letters later in alphabetic order. For example, the letter ‘A’ is replaced by ‘F’, ‘B’ is replaced by ‘G’ and so on. Note that the letter ‘A’ is considered to be following Z.
(a) What would the word ‘technology’ be stored as?
(b) What is the meaning of the following text? HTWWJHY
6. What is meant by the term ‘archiving’?
7. What is the purpose of a password?
8. What is a firewall?
9. What is a hacker?
