MCQOPTIONS
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MCQOPTIONS
This section includes 20 Mcqs, each offering curated multiple-choice questions to sharpen your Digital Communications knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
Which algorithm can be used to sign a message? |
| A. | Public key algorithm |
| B. | Private key algorithm |
| C. | Public & Private key algorithm |
| D. | None of the mentioned |
| Answer» B. Private key algorithm | |
| 2. |
Cipher system can be solved effectively by statistically using |
| A. | Time of occurrence |
| B. | Frequency of occurrence |
| C. | Length of the message |
| D. | None of the mentioned |
| Answer» C. Length of the message | |
| 3. |
A set of numbers is called as super increasing if |
| A. | Each element is greater than previous element |
| B. | Each element greater than sum of all the previous elements |
| C. | Each element greater than the average of all elements |
| D. | Each element lesser than the sum of all the elements |
| Answer» C. Each element greater than the average of all elements | |
| 4. |
In stream encryption, the key sequence repeats itself. |
| A. | True |
| B. | False |
| Answer» C. | |
| 5. |
Which should be used first to decrypt? |
| A. | Public key |
| B. | Private key |
| C. | Public & Private key |
| D. | None of the mentioned |
| Answer» C. Public & Private key | |
| 6. |
For n input bits the number of substitution patterns are |
| A. | 2n |
| B. | (2n)! |
| C. | 1/2n! |
| D. | 2n! |
| Answer» C. 1/2n! | |
| 7. |
The substitution of the letters are done |
| A. | Serially |
| B. | Parallel way |
| C. | Serially & Parallel way |
| D. | None of the mentioned |
| Answer» C. Serially & Parallel way | |
| 8. |
In transposition, the plaintext letters are |
| A. | Substituted |
| B. | Rearranged |
| C. | Removed |
| D. | None of the mentioned |
| Answer» C. Removed | |
| 9. |
A cryptographic hash function has variable output length. |
| A. | True |
| B. | False |
| Answer» C. | |
| 10. |
In cipher feedback method, encryption is done on |
| A. | Single individual bits |
| B. | Characters |
| C. | Single individual bits & Characters |
| D. | None of the mentioned |
| Answer» B. Characters | |
| 11. |
Encryption transformations are known as |
| A. | Diffusion |
| B. | Confusion |
| C. | Diffusion & Confusion |
| D. | None of the mentioned |
| Answer» D. None of the mentioned | |
| 12. |
Synchronous ciphers uses |
| A. | Confusion |
| B. | Diffusion |
| C. | Confusion & Diffusion |
| D. | None of the mentioned |
| Answer» B. Diffusion | |
| 13. |
Which should be kept as a secret in public key cryptosystem? |
| A. | Encryption key |
| B. | Decryption key |
| C. | Encryption & Decryption key |
| D. | None of the mentioned |
| Answer» C. Encryption & Decryption key | |
| 14. |
Euler's totient function is determined by |
| A. | pq |
| B. | (p-1)(q-1) |
| C. | (p+1)(q+1) |
| D. | p/q |
| Answer» C. (p+1)(q+1) | |
| 15. |
Examples of hash functions are |
| A. | MD5 |
| B. | SHA-1 |
| C. | MD5 & SHA-1 |
| D. | None of the mentioned |
| Answer» D. None of the mentioned | |
| 16. |
Public key cryptosystem uses same key for both encryption and decryption. |
| A. | True |
| B. | False |
| Answer» C. | |
| 17. |
In which method, key-stream is generated independently? |
| A. | Synchronous |
| B. | Self synchronous |
| C. | Synchronous & Self synchronous |
| D. | None of the mentioned |
| Answer» B. Self synchronous | |
| 18. |
What is the key size allowed in PGP? |
| A. | 1024-1056 |
| B. | 1024-4056 |
| C. | 1024-4096 |
| D. | 1024-2048 |
| Answer» D. 1024-2048 | |
| 19. |
Public key cryptosystem is also known as |
| A. | One way function |
| B. | Two way function |
| C. | Feedback function |
| D. | None of the mentioned |
| Answer» B. Two way function | |
| 20. |
Which algorithm is used for public key encryption? |
| A. | RSA |
| B. | Diffie-Hellman |
| C. | RSA & Diffie-Hellman |
| D. | None of the mentioned |
| Answer» D. None of the mentioned | |