Which method of encryption uses a pair consisting of a public key and a private key?
- A.Symmetric encryption
- B.Asymmetric encryption
- C.Hashing
- D.Compression
Correct answer
Explanation
The correct answer is B, asymmetric encryption, also called public key encryption. Anyone may hold the public key and use it to encrypt a message, but only the holder of the matching private key can decrypt it, so no secret has to be exchanged in advance; RSA is the standard example, and the same pair used the other way round produces a digital signature. Option A is wrong because symmetric encryption, such as AES or the older DES, uses one shared secret key for both operations and is fast but requires a safe way to pass that key. Option C is wrong because hashing is a one-way function that turns data into a fixed length digest for checking integrity and cannot be reversed to recover the message. Option D is wrong because compression only reduces the size of a file and provides no secrecy at all.
Read the full article: Cyber Security and Threats: Malware, Attacks and PYQs
Practice Questions
View allWhich of the following is a type of cyber attack that involves tricking users into revealing sensitive information?
- A.Phishing attack
- B.SQL injection attack
- C.DoS attack
- D.None of the above
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Phishing sends a message that looks as if it came from a bank, an employer or a government office, and asks the reader to confirm a password, a card number or a one-time password on a page that belongs to the attacker; the target of the attack is the person…
Read the full explanation →What is the purpose of a firewall in cyber security?
- A.To allow unrestricted access to a network
- B.To block unauthorised access to a network
- C.To create a backup of a network's data
- D.None of the above
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A firewall sits between a trusted internal network and the untrusted world outside, inspects the traffic crossing it and permits only what its rules allow, dropping the rest; it may be a hardware appliance, a software program or both together.
Read the full explanation →What is the term for a cyber security attack that targets multiple interconnected devices simultaneously to create a large-scale attack network?
- A.DDoS attack
- B.Botnet attack
- C.Zero-day attack
- D.Spear phishing attack
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A botnet is built by infecting many connected devices, each of which becomes a zombie obeying a single controller; the network so assembled is then rented out or used for spam, fraud or a flood of traffic.
Read the full explanation →The feature(s) of cyber security is/are:
- A.Compliance
- B.Defence against internal threats
- C.Threat prevention
- D.All of the above
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The correct answer is D, all of the above, because cyber security is not one activity but a programme that covers all three.
Read the full explanation →In the CIA triad of information security, the letter I stands for:
- A.Identification
- B.Integrity
- C.Internet
- D.Isolation
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The triad names the three goals of information security: confidentiality, that only authorised people can read the data; integrity, that the data is complete and unaltered from the moment it was created or sent; and availability, that the system works when an authorised user needs it.
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