Cyber Security — Study Notes

1. Introduction

Cyber security is the practice of protecting computers, mobile phones, networks, programs and data from digital attacks, theft and damage. As more of our life moves online, criminals also move online, so every user must learn to stay safe. The people who break into computers or harm others on the Internet are called cyber criminals or hackers, and the harmful programs they use are called malware. Cyber security includes keeping our devices safe, protecting our personal information, creating strong passwords, and knowing how to react when something goes wrong.

2. Malware and Viruses

Malware, short for malicious software, is any program designed to harm a computer. The most common type of malware is the virus, a program that attaches itself to other files and spreads from one computer to another. A worm spreads by itself across a network without attaching to files. A Trojan horse pretends to be a useful program but secretly damages the system. Spyware secretly watches what the user does and steals information. Ransomware locks the user's files and demands money to unlock them, and adware shows unwanted advertisements. All of these are grouped under the single name malware.

3. How Malware Enters a Computer

Malware enters a computer in several common ways. It can come attached to an email or a message from an unknown sender. It can be hidden inside free downloads, games or pirated software. It can arrive on a pen drive or CD borrowed from another person. It can be downloaded automatically from a harmful website, a trick called a drive-by download. A phishing attack sends a fake message that looks like it comes from a real bank or company, asking the user to click a link and enter passwords, which are then stolen. Knowing these entry points is the first step in protection.

4. Passwords and Strong Authentication

A password is the key that protects an account, so a weak password is like leaving the door open. A strong password should be at least eight characters long, and it should mix small letters, capital letters, numbers and special symbols, for example N@vy@2024. It must never be the user's name, date of birth or the word "password". Each account should have a different password, and the password must be changed regularly and kept secret. Two-factor authentication (2FA) adds a second step, such as a code sent to the mobile phone, making the account much harder to break into.

5. Safe Browsing Habits

Staying safe while browsing means making careful choices. The user should type website addresses directly or use bookmarks instead of clicking unknown links. A secure website shows https at the beginning of its address and a padlock symbol in the browser, which means the data sent to that site is encrypted. The user must avoid entering personal or banking details on sites without the padlock. Pop-ups offering prizes or warnings should be closed without clicking, and software and antivirus should always be kept up to date.

6. Antivirus and Protective Software

An antivirus program scans the computer, finds viruses and malware, and removes them. It should run a full system scan regularly, and it must be updated with new virus definitions because new viruses appear every day. The firewall is a security system, built into the operating system, that watches all data entering and leaving the computer and blocks suspicious traffic. Anti-spyware and anti-phishing tools give extra protection, and the operating system and all applications should have the latest security updates installed, because updates often repair security holes.

7. Social Media Safety and Cyberbullying

On social media, users share pictures and messages, so privacy settings must be checked carefully so that posts are not seen by strangers. Cyberbullying is using the Internet to threaten, tease or embarrass someone, and it includes sending mean messages, spreading rumours and posting hurtful photos. A victim of cyberbullying must never reply with anger; instead, the messages should be saved as evidence, the bully should be blocked, and the incident should be reported to parents, teachers or the police. Online predators are strangers who try to become friends only to harm children, and they must always be reported.

8. Identity Theft and Reporting

Identity theft happens when a criminal steals personal details such as the name, phone number and bank card number, and uses them to cheat or to commit crimes in the victim's name. Personal information should never be posted publicly online. If identity theft or any cyber crime happens, the user must change passwords immediately, inform the bank if money is involved, save the evidence, and report the matter to the cyber crime cell or the police. Reporting helps catch the criminal and protects other people too. Staying alert and careful is the best defence against all cyber threats.

Quick Revision Tables

Table 1: Types of Malware

Table 2: Safety Rules

Mind Map

Important Diagrams (SVG)

Diagram 1: Cyber Threats and Defences

Diagram 2: Features of a Strong Password

Common Mistakes

1. Saying a virus and a worm are the same. A worm spreads by itself; a virus needs to attach to a file.
2. Believing only poor countries face cyber crime. Cyber crime happens everywhere in the world.
3. Using the same password for all accounts. Each account must have a different password.
4. Writing "https" and "http" are equal. The s in https means secure and the data is encrypted.
5. Opening an attachment from an unknown sender. This is how most malware enters the computer.
6. Responding angrily to a cyberbully. Never reply; save the evidence and report to an adult.
7. Thinking free downloads from unknown sites are always safe. Pirated and unknown downloads often carry malware.
8. Keeping the antivirus switched off to make the computer faster. Antivirus and updates must always be on.

Exam Tips

1. Define malware first and then explain virus, worm, Trojan, spyware and ransomware with one line each.
2. List the ways malware enters a computer as four numbered points for full marks.
3. Write the five rules of a strong password from the diagram in your own words.
4. Mention the padlock symbol and https when writing about safe websites.
5. Explain cyberbullying and give two correct actions: save evidence and report it.
6. State that the cyber crime cell is where cyber crimes must be reported.
7. Finish the answer with the sentence "Prevention is better than cure" for a good conclusion.

Conclusion

Cyber security is the shield that protects us in the digital world. Malware such as viruses, Trojans and ransomware threatens every connected device, but antivirus software, firewalls, strong passwords and regular updates defend against them. Safe browsing habits, careful social media use and quick reporting of cyberbullying keep both data and people safe. With these safety skills in place, we can now learn to build our own web pages using HTML, the language of the World Wide Web.