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Digital Communications Multiple Choice Questions | MCQs | Quiz

Digital Communication Interview Questions and Answers
Pratice Digital Communication questions and answers for interviews, campus placements, online tests, aptitude tests, quizzes and competitive exams.

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•   Signal Processing
•   Signal Classification
•   Spectral Density
•   Random Signals
•   Baseband System
•   Noise - 1
•   Noise - 2
•   Digital Communication
•   DC System - 1
•   DC System - 2
•   Process Types
•   Signals
•   Analog Information
•   Corruption Sources
•   Pulse Code Modulation
•   Non Uniform Quantization
•   Baseband Transmission - 1
•   Baseband Transmission - 2
•   Correlative Coding
•   Sampling & Quantization - 1
•   Sampling & Quantization - 2
•   Signals & Noises
•   Intersymbol Interference - 1
•   Intersymbol Interference - 2
•   Equalization
•   Non Coherent Detection
•   Bandpass Techniques
•   Coherent Detection
•   M-ary Signalling
•   Link Budget Analysis
•   Link Budget Error Control
•   Noise Parameters
•   Waveform Coding
•   Structured Sequence
•   Error Detection
•   Linear Block Codes
•   Convolution Encoding
•   Reed Solomon Code
•   Concatenated Codes
•   Shannon Hartley Theorem
•   Bandwidth Modulation
•   Communication Resources
•   Trellis Coded Modulation
•   PAM, PWM & TDM
•   M-ary Modulation
•   Modulation & Multiplexing
•   Modulation & Entropy
•   Modulation Techniques
•   Network Synchronization
•   Receiver Synchronization
•   Spread Spectrum & TDMA
•   Access Algorithm
•   INTELSAT
•   TDM & FDM
•   TDM vs FDM
•   Spread Spectrum & CDMA
•   Pseudo Noise Sequence
•   Frequency Hopping
•   Acquisition & Tracking
•   Cellular Systems
•   Cipher Systems Secrecy
•   Stream Encryption
•   Spread Spectrum
•   Public Key Cryptosystems1
•   Public Key Cryptosystems2
•   Pretty Good Privacy
•   Mobile Radio Propagation
•   Signal Time Spreading
•   Rake Receivers
•   Decision Theory Effects
•   Abstraction & Layering
•   Protocols
•   Random Processes
•   ISDN & Interface
•   Error Detection - 1
•   Error Detection - 2
•   Codes & Coding Technique
•   Interpolation
•   Information & Coding
•   Quantization - 1
•   Quantization - 2

Best Reference Books

Digital Communication Books
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Digital Communications Questions and Answers – Public Key Cryptosystems 1

Posted on November 3, 2015 by Manish

This set of Digital Communications Multiple Choice Questions & Answers (MCQs) focuses on “Public key cryptosystem 1”.

1. In public key cryptosystem _____ keys are used for encryption and decryption.
a) Same
b) Different
c) Encryption Keys
d) None of the mentioned
View Answer

Answer: b
Explanation: In conventional cryptosystem same keys are used for encryption and decryption where as in public key cryptosystem different keys are used.

2. In public key cryptosystem which is kept as public?
a) Encryption keys
b) Decryption keys
c) Encryption & Decryption keys
d) None of the mentioned
View Answer

Answer: a
Explanation: In public key cryptosystem, the encryption keys are kept as public where as decryption keys are kept as secret.

3. In a trapdoor function, the functions are easy to go in
a) One direction
b) Two directions
c) All directions
d) None of the mentioned
View Answer

Answer: a
Explanation: A trapdoor is a one way function. Such functions can go easily in only one direction.

4. Pretty good privacy program is used for
a) Electronic mails
b) File encryption
c) Electronic mails & File encryption
d) None of the mentioned
View Answer

Answer: c
Explanation: Pretty good privacy (PGP) privacy program is used for both electronic mails and file encryption.

5. PGP system uses
a) Private key system
b) Public key system
c) Private & Public key system
d) None of the mentioned
View Answer

Answer: c
Explanation: Pretty good privacy system uses both private key and public key based systems.

6. Private key algorithm is used for _____ encryption and public key algorithm is used for _____ encryption.
a) Messages, session key
b) Session key, messages
c) Can be used for both
d) None of the mentioned
View Answer

Answer: a
Explanation: Private key algorithm is used for encryption of messages and public key algorithm is used for encryption of session keys.

7. Which are called the block ciphers?
a) IDEA
b) CAST
c) Triple-DES
d) All of the mentioned
View Answer

Answer: d
Explanation: Some of the examples of block codes are triple-DES, CAST and IDEA.

8. Which has a key length of 128 bits?
a) IDEA
b) Triple-DES
c) IDEA & Triple-DES
d) None of the mentioned
View Answer

Answer: a
Explanation: Triple-DES uses 168 bit key size and IDEA and CAST uses 128 bits key length.

9. 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
View Answer

Answer: a
Explanation: Public key algorithms are used to sign a message and private key algorithms are used to encrypt the messages.

10. Examples of hash functions are
a) MD5
b) SHA-1
c) MD5 & SHA-1
d) None of the mentioned
View Answer

Answer: c
Explanation: Some examples of hash functions are MD5 and SHA-1.

11. A cryptographic hash function has variable output length.
a) True
b) False
View Answer

Answer: b
Explanation: A cryptographic hash function has fixed output length.

12. 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
View Answer

Answer: b
Explanation: A set of numbers is called as super increasing if each element is greater than the sum of all the numbers lesser than it.

13. Knapsack problem can be solved by
a) Public key cryptosystem
b) Private key cryptosystem
c) Public & Private key cryptosystem
d) None of the mentioned
View Answer

Answer: a
Explanation: The knapsack problem can be solved by public key cryptosystem system using knapsack vector and data vector.

14. Merkle hellman is a symmetric cryptosystem.
a) True
b) False
View Answer

Answer: b
Explanation: Merkell hellman cryptosystem is a public key asymmetric cryptosystem method.

15. In this Merkle Hellman method same key is used for encryption and decryption.
a) True
b) False
View Answer

Answer: b
Explanation: In Merkle hellman cryptosystem method, two separate private and public keys are used for encryption and decryption.

Sanfoundry Global Education & Learning Series – Digital Communications.

To practice all areas of Digital Communications, here is complete set of 1000+ Multiple Choice Questions and Answers.

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