MCQOPTIONS
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MCQOPTIONS
This section includes 62 Mcqs, each offering curated multiple-choice questions to sharpen your Cryptography and Network Security knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
Confidentiality can only be provided if we perform message encryption before the MAC generation. |
| A. | True |
| B. | False |
| Answer» C. | |
| 2. |
The following figure has authentication tied to the plaintext- |
| A. | True |
| B. | False |
| Answer» C. | |
| 3. |
The above figure represents internal error control. |
| A. | True |
| B. | FalseView Answer |
| Answer» C. | |
| 4. |
The above figure implements authentication and signature only? |
| A. | True |
| B. | FalseView Answer |
| Answer» B. FalseView Answer | |
| 5. |
The criticality indicator indicates whether an extension can be safely ignored. |
| A. | True |
| B. | False |
| C. | May be |
| D. | Can't say |
| Answer» B. False | |
| 6. |
Which of these systems use timestamps as an expiration date? |
| A. | Public-Key Certificates |
| B. | Public announcements |
| C. | Publicly available directories |
| D. | Public-Key authority |
| Answer» B. Public announcements | |
| 7. |
“Meet in the middle attack” and “man in the middle attack” are the same. |
| A. | True |
| B. | False |
| C. | May be |
| D. | Can't say |
| Answer» C. May be | |
| 8. |
Which session key is used for electronic funds transfer and point of sale applications? |
| A. | Data-encrypting key |
| B. | File-encrypting key |
| C. | PIN-encrypting key |
| D. | None of the mentioned |
| Answer» D. None of the mentioned | |
| 9. |
Sometimes a simple tag is introduced along with the session key. This tag has 8 bits. Which of the following options is wrong? |
| A. | One bit indicates whether the key is a session key or a master key |
| B. | One bit indicates whether the key can be used for encryption |
| C. | Three bit indicates whether the key can be used for decryption |
| D. | Remaining bits are for future use |
| Answer» D. Remaining bits are for future use | |
| 10. |
Hash Value = H = h(CV)Key Input = Km XOR HCiphertext = E([Km XOR H],Ks)What is CV here? |
| A. | Cipher vector |
| B. | Current vector |
| C. | Control vector |
| D. | None of the mentioned |
| Answer» D. None of the mentioned | |
| 11. |
“Meet in the middle attack” is an attack |
| A. | where the timing required for the attack via brute force is drastically reduced |
| B. | where the adversary uses 2 or more machines to decrypt thus trying to reduce the time |
| C. | where messages are intercepted and then either relayed or substituted with another message |
| D. | where cryptanalysis takes lesser time than the brute force decryption |
| Answer» D. where cryptanalysis takes lesser time than the brute force decryption | |
| 12. |
How many add round key functions are present in the Whirlpool algorithm? |
| A. | 16 |
| B. | 18 |
| C. | 11 |
| D. | 10 |
| Answer» D. 10 | |
| 13. |
There’s no known successful attacks made against Whirlpool. |
| A. | True |
| B. | False |
| C. | May be |
| D. | Can't say |
| Answer» B. False | |
| 14. |
The Round Constant is given by S[8(r-1)+j]. What are the limits of ‘r’? |
| A. | 0 <= r <= 11 |
| B. | 0 <= r <= 12 |
| C. | 0 <= r <= 10 |
| D. | 0 <= r <=16 |
| Answer» D. 0 <= r <=16 | |
| 15. |
The 7th row in the 8 × 8 matrix undergoes a ___________ shift. |
| A. | 6 bit |
| B. | 6 byte |
| C. | 7 bit |
| D. | 7 byte |
| Answer» C. 7 bit | |
| 16. |
How many XOR gate operations are involved in the S-box permutation? |
| A. | 12 |
| B. | 8 |
| C. | 16 |
| D. | 4 |
| Answer» B. 8 | |
| 17. |
Which Authentication Encryption approach is taken by the SSH protocol? |
| A. | Hashing followed by encryption (H→E) |
| B. | Encryption followed by authentication (E→A) |
| C. | Authentication followed by encryption (A→E) |
| D. | Independently encrypt and authenticate (E + A) |
| Answer» E. | |
| 18. |
In GCM, we define S as S = GHASH(A||0^v||C||0^u||[len(A)]||[len(C)]). What is v defined as? |
| A. | 64 ceil[len (A)/128] – len (A) |
| B. | 64 ceil[len (C)/128] – len (C) |
| C. | 128 ceil[len (A)/128] – len (A) |
| D. | 128 ceil[len (C)/128] – len (C) |
| Answer» D. 128 ceil[len (C)/128] – len (C) | |
| 19. |
The hash matrix of 8 × 8 is preferred over a 16 × 4 matrix because |
| A. | it is symmetric |
| B. | it is smaller in size |
| C. | it is faster in computation |
| D. | none of the mentioned |
| Answer» D. none of the mentioned | |
| 20. |
How many rounds are there in one Whirlpool Iteration? |
| A. | 3 |
| B. | 4 |
| C. | 6 |
| D. | 8 |
| Answer» C. 6 | |
| 21. |
For a 100 bit key and a 32 bit tag, how many possible keys can be produced in the 3rd round? |
| A. | 2^4 |
| B. | 2^32 |
| C. | 2^16 |
| D. | 2^64 |
| Answer» B. 2^32 | |
| 22. |
MACs are also called |
| A. | testword |
| B. | checkword |
| C. | testbits |
| D. | none of the mentioned |
| Answer» E. | |
| 23. |
Publicly Available directory is more secure than which other system? |
| A. | Public-Key Certificates |
| B. | Public announcements |
| C. | Public-Key authority |
| D. | None of the mentioned |
| Answer» C. Public-Key authority | |
| 24. |
Which is the correct representation for session key recovery for the plain text? |
| A. | D ([Km XOR H], E([Km XOR H], Ks) |
| B. | D([Km XOR H],Ks) |
| C. | D ([Km XOR H], E([Km XOR H]) |
| D. | None of the mentioned |
| Answer» B. D([Km XOR H],Ks) | |
| 25. |
What is the size of the key in the algorithm? |
| A. | 256 bits |
| B. | 512 bits |
| C. | 128 bits |
| D. | 1024 bits |
| Answer» C. 128 bits | |
| 26. |
When the Round Constant is given by S[8(r-1)+j]. What are the limits of ‘i’ and ‘j’? |
| A. | i = 1 ; 0 <= j <= 7 |
| B. | i = 0 ; 0 <= j <= 7 |
| C. | 0 <= i <= 7; 0 <= j <= 7 |
| D. | 0 <= i <= 7; j=0 |
| Answer» C. 0 <= i <= 7; 0 <= j <= 7 | |
| 27. |
Larger networks would prefer a full decentralization. |
| A. | True |
| B. | False |
| C. | May be |
| D. | Can't say |
| Answer» C. May be | |
| 28. |
Which of the following is required to find the session key?i) Control Vectorii) Master Keyiii) Encrypted session Key |
| A. | i) |
| B. | i) and ii) |
| C. | i) and iii) |
| D. | i) ii) and iii) |
| Answer» E. | |
| 29. |
Which system uses a trusted third party interface? |
| A. | Public-Key Certificates |
| B. | Public announcements |
| C. | Publicly available directories |
| D. | Public-Key authority |
| Answer» B. Public announcements | |
| 30. |
Hashing followed by encryption (H→E) is used by which algorithm? |
| A. | IPSec |
| B. | SSH |
| C. | WEP |
| D. | SSL/TLS |
| Answer» D. SSL/TLS | |
| 31. |
Each round uses a different key in the algorithm. |
| A. | True |
| B. | False |
| C. | May be |
| D. | Can't say |
| Answer» B. False | |
| 32. |
The 8 × 8 hash matrix holds values of size |
| A. | 16 bits |
| B. | 32 bits |
| C. | 8 bits |
| D. | 4 bits |
| Answer» D. 4 bits | |
| 33. |
MAC is a |
| A. | one-to-one mapping |
| B. | many-to-one mapping |
| C. | onto mapping |
| D. | none of the mentioned |
| Answer» C. onto mapping | |
| 34. |
Suppose that A has obtained a certificate from certification authority X1 and B has obtained certificate authority from CA X2. A can use a chain of certificates to obtain B’s public key. In notation of X.509, this chain is represented in the correct order as – |
| A. | X2 X1 X1 B |
| B. | X1 X1 X2 A |
| C. | X1 X2 X2 B |
| D. | X1 X2 X2 A |
| Answer» D. X1 X2 X2 A | |
| 35. |
Mix Row functions operate on the 8 × 8 matrix (A) to form the new matrix. The operation can be considered to be B = AC. The matrix C is formed by |
| A. | each successive even row having left shifts |
| B. | each successive row having a left shifts |
| C. | each successive odd row having right shifts |
| D. | each successive row having a right shifts |
| Answer» E. | |
| 36. |
Which one of these is not a Whirlpool function? |
| A. | Add Key |
| B. | Substitute Bytes |
| C. | Mix Rows |
| D. | Shift Rows |
| Answer» E. | |
| 37. |
Which of these is not a type of session key? |
| A. | PIN-encrypting key |
| B. | File-encrypting key |
| C. | Session encrypting key |
| D. | Data encrypting key |
| Answer» D. Data encrypting key | |
| 38. |
Which systems use a timestamp?i) Public-Key Certificatesii) Public announcementsiii) Publicly available directoriesiv) Public-Key authority |
| A. | i) and ii) |
| B. | iii) and iv) |
| C. | i) and iv) |
| D. | iv) only |
| Answer» D. iv) only | |
| 39. |
CMS stands for |
| A. | cipher message syntax |
| B. | certificate message session |
| C. | cryptographic message syntax |
| D. | none of the mentioned |
| Answer» D. none of the mentioned | |
| 40. |
How many handshake rounds are required in the Public-Key Distribution Scenario? |
| A. | 7 |
| B. | 5 |
| C. | 3 |
| D. | 4 |
| Answer» B. 5 | |
| 41. |
CMP stands for |
| A. | cipher message protocol |
| B. | cipher management protocol |
| C. | certificate message protocol |
| D. | none of the mentioned |
| Answer» E. | |
| 42. |
How many functions are involved in the PKIX architectural model? |
| A. | 3 |
| B. | 5 |
| C. | 6 |
| D. | 7 |
| Answer» E. | |
| 43. |
The issuer unique identifier of the X.509 certificates was added in which version? |
| A. | 1 |
| B. | 2 |
| C. | 3 |
| D. | 4 |
| Answer» C. 3 | |
| 44. |
A total of seven messages are required in the Public-Key distribution scenario. However, the initial five messages need to be used only infrequently because both A and B can save the other’s public key for future – a technique known as ____ |
| A. | time stamping |
| B. | polling |
| C. | caching |
| D. | squeezing |
| Answer» D. squeezing | |
| 45. |
For an n-bit tag and a k-bit key, the level of effort required for brute force attack on a MAC algorithm is |
| A. | 2^k |
| B. | 2^n |
| C. | min(2^k,2^n) |
| D. | 2^k/2^n |
| Answer» D. 2^k/2^n | |
| 46. |
X.509 certificate recommends which cryptographic algorithm? |
| A. | RSA |
| B. | DES |
| C. | AES |
| D. | Rabin |
| Answer» B. DES | |
| 47. |
The period of validity consists of the date on which the certificate expires. |
| A. | True |
| B. | False |
| C. | May be |
| D. | Can't say |
| Answer» C. May be | |
| 48. |
What is the value of opad in the HMAC structure? |
| A. | 00111110 |
| B. | 00110010 |
| C. | 10110110 |
| D. | 01011100 |
| Answer» E. | |
| 49. |
“Conveys any desired X.500 directory attribute values for the subject of this certificate.”Which Extension among the following does this refer to? |
| A. | Subject alternative name |
| B. | Issuer Alternative name |
| C. | Subject directory attributes |
| D. | None of the mentioned |
| Answer» D. None of the mentioned | |
| 50. |
Which round provides linear diffusion in the Whirlpool Algorithm? |
| A. | Add Key |
| B. | Substitute Bytes |
| C. | Mix Rows |
| D. | Shift Rows |
| Answer» D. Shift Rows | |