Computer Security Basics Questions for IBPS RRB PO

Core Concept: What is Computer Security

Computer security means protecting computer systems, networks, and data from theft, damage, or unauthorized access. Think of it like a bank vault — the vault door is the firewall, the guard is the antivirus, and the secret combination is encryption. In rural banking (RRB context), computer security is critical because digital transactions and customer data must be protected at all times.

• Three pillars of security: Confidentiality, Integrity, Availability — called the CIA Triad
• Confidentiality: only authorized people can see data
• Integrity: data is not altered without permission
• Availability: systems and data are accessible when needed
• Authentication: verifying who you are (password, OTP, biometric)
• Authorization: deciding what you are allowed to do after login

Types of Malware (Malicious Software)

Malware is any software designed to harm a computer or steal data. This is the highest-frequency subtopic in exams. Each type has a distinct behavior — learn them like characters in a story. The Virus spreads by attaching to files (like a cold virus needs a host). The Worm travels on its own through networks (like a worm moves without needing to attach). The Trojan pretends to be useful software but is actually harmful inside (like the Trojan horse from history).

• Virus: attaches to a file, needs human action to spread
• Worm: self-replicates across networks without human help
• Trojan Horse: disguises as legitimate software, allows backdoor access
• Ransomware: locks your files and demands money (ransom) to unlock — very common in recent exams
• Spyware: secretly monitors user activity and sends data to attacker
• Adware: displays unwanted advertisements, often bundled with free software
• Rootkit: hides deep in the system to give attacker long-term hidden control
• Keylogger: records every keystroke — steals passwords silently

Cyber Attack Types

Beyond malware, attackers use specific techniques to break into systems. Phishing is the most commonly tested attack — it is a fake email or website that tricks users into giving away passwords or bank details. Think of phishing like a fisherman casting a fake bait. Pharming redirects users to a fake website even if they type the correct URL. DoS and DDoS attacks flood a server with fake requests so it crashes and real users cannot access it.

• Phishing: fake emails or sites to steal credentials — most common attack type in exams
• Pharming: hijacks DNS to redirect to a fake website without the user knowing
• Spoofing: faking identity — IP spoofing, email spoofing
• DoS (Denial of Service): one machine floods a server to make it crash
• DDoS (Distributed DoS): many machines (botnet) attack a server simultaneously
• Man-in-the-Middle (MitM): attacker secretly intercepts communication between two parties
• Brute Force Attack: trying all possible password combinations until one works
• SQL Injection: inserting malicious SQL code into a database input field

Firewall and Antivirus

A Firewall is a security system that monitors and controls incoming and outgoing network traffic based on predefined rules. Think of it as a security guard at the gate of a building who checks everyone entering and leaving. Antivirus software detects, prevents, and removes malware from a computer. It works by comparing files against a database of known malware signatures.

• Firewall can be hardware-based, software-based, or both
• Firewall filters traffic using rules — blocks unauthorized access
• Antivirus uses signature-based detection to identify known malware
• Heuristic analysis in antivirus helps catch new or unknown malware
• Intrusion Detection System (IDS): monitors network for suspicious activity and alerts
• Intrusion Prevention System (IPS): monitors AND actively blocks suspicious activity

Encryption and Cryptography

Encryption converts readable data (plaintext) into unreadable scrambled form (ciphertext) using a key, so only authorized people can read it. It is like writing a message in a secret code. Decryption is the reverse process. Two main types are Symmetric encryption (same key to lock and unlock) and Asymmetric encryption (public key to lock, private key to unlock).

• Symmetric encryption: one key for both encryption and decryption — fast, used for bulk data. Example: AES
• Asymmetric encryption: public key encrypts, private key decrypts. Example: RSA
• SSL/TLS: protocols that encrypt data between browser and server — seen as HTTPS in the URL
• Digital Signature: uses asymmetric encryption to verify identity and integrity of a message
• Hashing: converts data into a fixed-size hash value — one-way, cannot be reversed. Example: MD5, SHA
• VPN (Virtual Private Network): creates an encrypted tunnel over the internet for secure communication

Passwords and Authentication

Authentication confirms who you are. Modern systems use multi-factor authentication (MFA) which combines two or more of the following: something you know (password), something you have (OTP on phone), and something you are (fingerprint or face). This is extremely relevant in rural banking where biometric and OTP-based logins are common.

• Single-factor: only password — weakest form
• Two-Factor Authentication (2FA): password plus OTP — very common in banking apps
• Biometric authentication: fingerprint, iris, face recognition
• CAPTCHA: distinguishes human users from bots — Completely Automated Public Turing test
• Password best practices: long, mix of characters, no personal info, changed regularly

• Confusing Virus and Worm: Remember — a Virus needs a host file and human action; a Worm travels on its own. Worm = independent traveler.
• Mixing up DoS and DDoS: DoS is from one machine, DDoS is from many machines (Distributed = many).
• Thinking Phishing and Pharming are the same: Phishing tricks you via fake email or link; Pharming redirects you even if you type the correct address yourself.
• Confusing IDS and IPS: IDS only Detects and alerts; IPS Prevents by actively blocking. D for Detect, P for Prevent.
• Mixing Symmetric and Asymmetric encryption: Symmetric = same key for both; Asymmetric = two different keys (public and private). If you see RSA, it is always asymmetric.

• CIA Triad memory hook: Think of a CIA agent — they keep secrets (Confidentiality), do not tamper with evidence (Integrity), and are always available for a mission (Availability).
• Malware family acronym VWTRS: Virus, Worm, Trojan, Ransomware, Spyware — Very Weird Trojans Ransom Spies.
• Symmetric vs Asymmetric: Symmetric = Same key (both S words). Asymmetric = two keys, two words: Public and Private.
• Phishing vs Pharming: Phishing = you click a fake bait (you made a mistake). Pharming = you did nothing wrong but were still redirected (the system was poisoned — ph-ARM-ing like an armed ambush).

• In IBPS RRB PO Computer section, malware types and cyber attack names are the most repeated questions. Expect at least one direct definition question like what is ransomware or what does phishing mean.
• Questions are mostly one-liner definitions or match-the-column type. No calculations needed — pure memory and clarity of terms.
• Encryption terms like SSL, HTTPS, RSA, AES, and digital signatures appear regularly. Knowing which is symmetric vs asymmetric and where SSL is used is sufficient.
• Recent trend: questions on two-factor authentication, OTP-based login, and biometric security are increasing as RRBs push digital banking in rural areas — tie these answers to banking context.
• Time allocation tip: These are quick-scoring questions. If you have memorized the terms, each question should take under 30 seconds. Do not overthink — these are straightforward once you know the definition.