MCQOPTIONS
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MCQOPTIONS
This section includes 18 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. |
The _____ the uncertainty, the ______ is the information content. |
| A. | Lesser, greater |
| B. | Greater, lesser |
| C. | Lesser, lesser |
| D. | Greater, greater |
| Answer» E. | |
| 2. |
The conditions for perfect secrecy are |
| A. | Only one key transforming message should exist |
| B. | All keys should be equally likely |
| C. | One key transforming message to each cipher text & all keys should be equally likely |
| D. | None of the mentioned |
| Answer» D. None of the mentioned | |
| 3. |
A cipher system is said to have perfect secrecy if |
| A. | Posteriori probability is equal to priori probability |
| B. | Posteriori probability is greater than priori probability |
| C. | Posteriori probability is less than priori probability |
| D. | None of the mentioned |
| Answer» B. Posteriori probability is greater than priori probability | |
| 4. |
In Vigenere method ______ is provided. |
| A. | Priming key |
| B. | Feedback |
| C. | Priming key & Feedback |
| D. | None of the mentioned |
| Answer» D. None of the mentioned | |
| 5. |
A_CIPHER_SYSTEM_IS_SAID_TO_HAVE_PERFECT_SECRECY_IF?$ |
| A. | Posteriori probability is equal to priori probability |
| B. | Posteriori probability is greater than priori probability |
| C. | Posteriori probability is less than priori probability |
| D. | None of the mentioned |
| Answer» B. Posteriori probability is greater than priori probability | |
| 6. |
The _____ the uncertainty, the ______ is the information content.$ |
| A. | Lesser, greater |
| B. | Greater, lesser |
| C. | Lesser, lesser |
| D. | Greater, greater |
| Answer» E. | |
| 7. |
The_conditions_for_perfect_secrecy_are$ |
| A. | Only one key transforming message should exist |
| B. | All keys should be equally likely |
| C. | One key transforming message to each cipher text & all keys should be equally likely |
| D. | None of the mentioned |
| Answer» D. None of the mentioned | |
| 8. |
When a system is called as unbreakable? |
| A. | When unique solution is available |
| B. | When unique solution is not available |
| C. | All of the mentioned |
| D. | None of the mentioned |
| Answer» C. All of the mentioned | |
| 9. |
When the key size is finite, equivocation approaches |
| A. | Unity |
| B. | Zero |
| C. | Infinity |
| D. | None of the mentioned |
| Answer» C. Infinity | |
| 10. |
The maximum number of message bits contained in each character is called as |
| A. | True rate |
| B. | Absolute rate |
| C. | Optimum rate |
| D. | None of the mentioned |
| Answer» C. Optimum rate | |
| 11. |
In Vigenere method ______ is provided? |
| A. | Priming key |
| B. | Feedback |
| C. | Priming key & Feedback |
| D. | None of the mentioned |
| Answer» D. None of the mentioned | |
| 12. |
In auto key method |
| A. | Feedback is necessary |
| B. | Feedback is not necessary |
| C. | Can be either necessary or not |
| D. | None of the mentioned |
| Answer» B. Feedback is not necessary | |
| 13. |
The trithemius cipher is a mono alphabetical cipher. |
| A. | True |
| B. | False |
| Answer» C. | |
| 14. |
In Caesar cipher, each plain text is replaced by |
| A. | Alphabet shift |
| B. | Numerals |
| C. | Symbols |
| D. | None of the mentioned |
| Answer» B. Numerals | |
| 15. |
Caesar cipher was a mono alphabetic cipher. |
| A. | True |
| B. | False |
| Answer» B. False | |
| 16. |
The system which has insufficient information available to crypt-analyst is |
| A. | One-time pad |
| B. | Unconditionally secure |
| C. | One-time pad & Unconditionally secure |
| D. | None of the mentioned |
| Answer» D. None of the mentioned | |
| 17. |
The key also contains a |
| A. | Plaintext |
| B. | Ciphertext |
| C. | Plaintext & Ciphertext |
| D. | None of the mentioned |
| Answer» D. None of the mentioned | |
| 18. |
Cryptosystems are used for |
| A. | Privacy |
| B. | Authentication |
| C. | Privacy & Authentication |
| D. | None of the mentioned |
| Answer» D. None of the mentioned | |