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1. What is homomorphic encryption?
   a. A method that allows computations on encrypted data without decrypting it first
   b. A way to decrypt data faster
   c. A type of malware
   d. A password encryption technique
   Answer: a. A method that allows computations on encrypted data without decrypting it firstgeeksforgeeks+1
2. Homomorphic encryption enables which of the following?
   a. Computation on ciphertext that produces an encrypted result equal to operations on plaintext
   b. Data deletion without trace
   c. Faster internet connection
   d. Virus scanning
   Answer: a. Computation on ciphertext that produces an encrypted result equal to operations on plaintextbrilliant+1
3. What is the primary use of homomorphic encryption?
   a. Secure data processing without exposing sensitive data
   b. Enhancing graphics on computers
   c. Compressing files
   d. Speeding up email delivery
   Answer: a. Secure data processing without exposing sensitive dataaionlinecourse+1
4. The ciphertext after homomorphic computation, when decrypted, matches what?
   a. The result of the same operations done on the plaintext
   b. Random data
   c. Original plaintext unaltered
   d. Only partially correct data
   Answer: a. The result of the same operations done on the plaintextgeeksforgeeks+1
5. Which is NOT a type of homomorphic encryption?
   a. Partially homomorphic encryption
   b. Fully homomorphic encryption
   c. Somewhat homomorphic encryption
   d. Hash-based encryption
   Answer: d. Hash-based encryptionencryptionconsulting+1
6. What does Partially Homomorphic Encryption allow?
   a. Only specific operations like addition or multiplication on encrypted data
   b. Unlimited operations on plaintext
   c. Decryption without keys
   d. No operations on encrypted data
   Answer: a. Only specific operations like addition or multiplication on encrypted dataencryptionconsulting+1
7. Fully Homomorphic Encryption supports which operations?
   a. Both addition and multiplication on encrypted data
   b. Only addition
   c. Only multiplication
   d. No operations
   Answer: a. Both addition and multiplication on encrypted datageeksforgeeks+1
8. Which year was Fully Homomorphic Encryption first solved?
   a. 2009
   b. 1999
   c. 2015
   d. 2023
   Answer: a. 2009brilliant+1
9. What is one major limitation of homomorphic encryption?
   a. It is slow compared to plaintext computation
   b. It cannot encrypt data
   c. It reveals data easily
   d. It only works on images
   Answer: a. It is slow compared to plaintext computationencryptionconsulting+1
10. What is bootstrapping in homomorphic encryption?
    a. A technique to refresh ciphertexts and reduce noise
    b. Encrypting data without keys
    c. Writing software to decrypt data
    d. A method to speed up network connections
    Answer: a. A technique to refresh ciphertexts and reduce noiseopenmined+1
11. Homomorphic encryption helps in which key area?
    a. Privacy-preserving data analysis
    b. Increasing screen resolution
    c. Faster downloads
    d. File compression
    Answer: a. Privacy-preserving data analysisaionlinecourse+1
12. Which cryptosystem is an example of additive homomorphic encryption?
    a. Paillier cryptosystem
    b. AES
    c. RSA without homomorphic properties
    d. DES
    Answer: a. Paillier cryptosystemgeeksforgeeks+1
13. Why is homomorphic encryption important for cloud computing?
    a. Enables computations on encrypted cloud data without exposure
    b. Speeds up cloud servers
    c. Prevents all hacking attempts
    d. Compresses cloud storage
    Answer: a. Enables computations on encrypted cloud data without exposureaionlinecourse+1
14. Which concept relates to the strength of encryption based on mathematical hardness problems?
    a. Lattice-based encryption
    b. Password strength
    c. Symmetric keys
    d. Hash functions
    Answer: a. Lattice-based encryptionoptalysys+1
15. How does homomorphic encryption contribute to machine learning?
    a. Enables training on encrypted data preserving privacy
    b. Improves graphics
    c. Reduces battery use
    d. Speeds up training by removing data encryption
    Answer: a. Enables training on encrypted data preserving privacyaionlinecourse+1
16. Which of the following is a type of Fully Homomorphic Encryption scheme?
    a. Gentry-BGV scheme
    b. RSA scheme
    c. MD5 hashing
    d. AES encryption
    Answer: a. Gentry-BGV schemeshaih.github+1
17. What kind of operations can Somewhat Homomorphic Encryption perform?
    a. Limited number of operations on encrypted data
    b. Unlimited operations
    c. Only text editing
    d. No operations at all
    Answer: a. Limited number of operations on encrypted datageeksforgeeks
18. Which key pair is used in homomorphic encryption?
    a. Public key for encryption, private key for decryption
    b. Public key for decryption only
    c. Only symmetric keys
    d. No keys needed
    Answer: a. Public key for encryption, private key for decryptionaionlinecourse
19. What is the output of performing addition on two ciphertexts in homomorphic encryption?
    a. The encrypted sum of plaintexts
    b. Random data
    c. The plaintext sum directly
    d. Only one ciphertext unchanged
    Answer: a. The encrypted sum of plaintextsencryptionconsulting
20. Homomorphic encryption is especially useful where?
    a. When collaborating on sensitive data without sharing raw data
    b. For open public data sharing
    c. For image compression
    d. For website design
    Answer: a. When collaborating on sensitive data without sharing raw datageeksforgeeks+1
21. What is the main security advantage of homomorphic encryption?
    a. Data remains encrypted throughout processing
    b. No need for passwords
    c. Faster processing than plaintext
    d. Automatically fixes data errors
    Answer: a. Data remains encrypted throughout processingaionlinecourse+1
22. Can homomorphic encryption be used for database queries?
    a. Yes, on encrypted databases without exposing data
    b. No, only for images
    c. Yes, but it decrypts data first
    d. No, it only encrypts emails
    Answer: a. Yes, on encrypted databases without exposing datageeksforgeeks+1
23. What type of noise impacts homomorphic encryption operations?
    a. Errors introduced during multiple computations on ciphertext
    b. Background static noise
    c. Noise from internet connections
    d. Mechanical noise in hardware
    Answer: a. Errors introduced during multiple computations on ciphertextopenmined+1
24. Homomorphic encryption helps prevent what type of risk?
    a. Exposure of sensitive data during processing
    b. Physical theft of hardware
    c. Software bugs
    d. Data loss through deletion
    Answer: a. Exposure of sensitive data during processingaionlinecourse+1
25. Which homomorphic encryption type offers a balance between performance and security?
    a. Somewhat Homomorphic Encryption
    b. Fully Homomorphic Encryption
    c. Partial Homomorphic Encryption
    d. Hash encryption
    Answer: a. Somewhat Homomorphic Encryptiongeeksforgeeks
26. The process of converting plaintext into encrypted ciphertext is called?
    a. Encryption
    b. Decryption
    c. Compression
    d. Hashing
    Answer: a. Encryptionaionlinecourse
27. Which operation is NOT possible on encrypted data through partially homomorphic encryption?
    a. Both addition and multiplication simultaneously
    b. Addition only
    c. Multiplication only
    d. Subtraction
    Answer: a. Both addition and multiplication simultaneouslygeeksforgeeks
28. What is “Evaluate” procedure in homomorphic encryption?
    a. Operation to compute on encrypted data without decrypting
    b. A way to decrypt the ciphertext
    c. Encrypting a message
    d. Key generation
    Answer: a. Operation to compute on encrypted data without decryptingshaih.github
29. Which scheme is known for enabling bootstrappable homomorphic encryption?
    a. Brakerski-Vaikuntanathan (BGV) scheme
    b. AES scheme
    c. DES scheme
    d. RSA scheme
    Answer: a. Brakerski-Vaikuntanathan (BGV) schemegeeksforgeeks
30. Homomorphic encryption can be combined with which tech to allow secure data outsourcing?
    a. Cloud computing
    b. Blockchain for cryptocurrency
    c. Virtual reality
    d. Internet of Things sensors
    Answer: a. Cloud computingaionlinecourse+1
31. In homomorphic encryption, who can decrypt the data?
    a. Only the holder of the private key
    b. Anyone on the network
    c. The cloud service provider
    d. The user who encrypts only
    Answer: a. Only the holder of the private keyaionlinecourse
32. What type of homomorphic encryption supports Boolean operations like AND, OR?
    a. Fully Homomorphic Encryption
    b. Partial Homomorphic Encryption
    c. Symmetric Encryption
    d. Somewhat Homomorphic Encryption
    Answer: a. Fully Homomorphic Encryptiongeeksforgeeks
33. How does lattice-based homomorphic encryption defend against attacks?
    a. It is resistant to quantum computer attacks
    b. By shortening keys frequently
    c. Using random passwords
    d. Through hardware firewalls
    Answer: a. It is resistant to quantum computer attacksoptalysys+1
34. What makes fully homomorphic encryption computationally intensive?
    a. Complex mathematical operations on encrypted data
    b. Simple addition only
    c. No encryption required
    d. Small key sizes
    Answer: a. Complex mathematical operations on encrypted dataencryptionconsulting+1
35. A main benefit of homomorphic encryption for healthcare data is:
    a. Analyzing patient data while keeping it confidential
    b. Faster MRI imaging
    c. Patient data deletion
    d. Reducing hospital bills
    Answer: a. Analyzing patient data while keeping it confidentialgeeksforgeeks
36. In the Paillier cryptosystem, what operation is homomorphic?
    a. Addition
    b. Multiplication
    c. Division
    d. XOR
    Answer: a. Additiongeeksforgeeks
37. Which key concept describes problems underlying secure homomorphic schemes?
    a. Learning With Errors (LWE)
    b. Hash collisions
    c. Password leaks
    d. Denial of Service
    Answer: a. Learning With Errors (LWE)optalysys
38. Homomorphic encryption allows data to remain secure during which stages?
    a. Storage, transmission, and computation
    b. Only transmission
    c. Only storage
    d. Only after decryption
    Answer: a. Storage, transmission, and computationaionlinecourse+1
39. Which is a drawback of using homomorphic encryption widely?
    a. High computational overhead
    b. It requires no keys
    c. Cannot protect data
    d. Data becomes smaller
    Answer: a. High computational overheadencryptionconsulting+1
40. Approximate homomorphic encryption is useful when:
    a. Small errors in results are acceptable
    b. Perfect accuracy is needed
    c. Only text data is used
    d. No encryption is needed
    Answer: a. Small errors in results are acceptablegeeksforgeeks
41. Which is an example of multiplicative homomorphism?
    a. ElGamal cryptosystem
    b. Paillier cryptosystem
    c. AES encryption
    d. RSA without homomorphism
    Answer: a. ElGamal cryptosystemgeeksforgeeks
42. Homomorphic encryption can facilitate what kind of collaboration?
    a. Secure multi-party computation without sharing raw data
    b. File sharing without encryption
    c. Social media posting
    d. Open source coding
    Answer: a. Secure multi-party computation without sharing raw dataaionlinecourse+1
43. What does noise refer to in homomorphic encryption?
    a. Error accumulated during ciphertext computations
    b. Background sound in hardware
    c. Internet interference
    d. Virus activity
    Answer: a. Error accumulated during ciphertext computationsopenmined
44. For which of these is homomorphic encryption NOT suited yet?
    a. Real-time all-purpose computation at scale due to slowness
    b. Performing a few encrypted operations
    c. Secure voting systems
    d. Cloud storage security
    Answer: a. Real-time all-purpose computation at scale due to slownessencryptionconsulting+1
45. Which is true about ciphertexts in homomorphic encryption?
    a. They can be manipulated without exposing plaintext
    b. They automatically decrypt during processing
    c. They cannot be used in computations
    d. They are always smaller than plaintext
    Answer: a. They can be manipulated without exposing plaintextgeeksforgeeks
46. What role does the public key play in homomorphic encryption?
    a. Used to encrypt data
    b. Used to decrypt data
    c. Generates random noise
    d. Signs messages only
    Answer: a. Used to encrypt dataaionlinecourse
47. Which is a key challenge in homomorphic encryption adoption?
    a. Computationally heavy and slow operations
    b. Lack of available keys
    c. Too easy to hack
    d. No practical applications
    Answer: a. Computationally heavy and slow operationsencryptionconsulting
48. Homomorphic encryption can be thought of as:
    a. Computing on locked boxes without opening them
    b. Storing data on paper
    c. Sending unencrypted data
    d. Simply compressing files
    Answer: a. Computing on locked boxes without opening thembrilliant
49. Which property is essential for homomorphic encryption correctness?
    a. Decrypt( Evaluate(Encrypt(m1), Encrypt(m2)) ) = m1 * m2 (for multiplication)
    b. Encryption skips decryption
    c. Keys change every second
    d. Results are approximate only
    Answer: a. Decrypt( Evaluate(Encrypt(m1), Encrypt(m2)) ) = m1 * m2 (for multiplication)shaih.github
50. How does homomorphic encryption affect data privacy?
    a. Maintains confidentiality even during processing
    b. Exposes data once processed
    c. Decreases security by design
    d. Does not encrypt at all
    Answer: a. Maintains confidentiality even during processingaionlinecourse+1

1. https://www.geeksforgeeks.org/ethical-hacking/homomorphic-encryption/
2. https://www.aionlinecourse.com/ai-basics/homomorphic-encryption
3. https://brilliant.org/wiki/homomorphic-encryption/
4. https://www.encryptionconsulting.com/introduction-to-homomorphic-encryption/
5. https://openmined.org/blog/what-is-homomorphic-encryption/
6. https://optalysys.com/resource/a-beginners-guide-to-fully-homomorphic-encryption-fhe/
7. https://shaih.github.io/pubs/he-chapter.pdf
8. https://arxiv.org/abs/2503.05136
9. https://www.zama.ai/introduction-to-homomorphic-encryption
10. https://www.splunk.com/en_us/blog/learn/homomorphic-encryption.html
11. https://study.com/academy/practice/quiz-worksheet-homomorphic-encryption.html
12. https://www.youtube.com/watch?v=DYgmqHntYkY
13. https://www.scribd.com/document/647946667/MCQ-Questions-cybersecurity
14. https://www.zama.ai/post/homomorphic-encryption-101
15. https://www.statcan.gc.ca/en/data-science/network/homomorphic-encryption
16. https://testbook.com/objective-questions/mcq-on-cryptography–5eea6a0939140f30f369d918
17. https://www.techtarget.com/searchsecurity/definition/homomorphic-encryption
18. https://www.scribd.com/document/784720829/Multiple-Choice-Questions
19. https://www.youtube.com/watch?v=SEBdYXxijSo
20. https://www.sanfoundry.com/1000-cryptography-network-security-questions-answers/