Explore topic-wise MCQs in Digital Communications.

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.

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
2.

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
3.

WHAT_IS_THE_KEY_SIZE_ALLOWED_IN_PGP??$

A. 1024-1056
B. 1024-4056
C. 1024-4096
D. 1024-2048
Answer» D. 1024-2048
4.

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
5.

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
6.

DSA protocol is based on

A. Discrete logarithm problem
B. Continuous logarithm problem
C. Discrete & Continuous logarithm problem
D. None of the mentioned
Answer» B. Continuous logarithm problem
7.

The hash function

A. Is collision free
B. Has manageable collision
C. Has high unmanageable level of collision
D. None of the mentioned
Answer» B. Has manageable collision
8.

In hash function output length is fixed.

A. True
B. False
Answer» B. False
9.

The digital signature provides authentication to the

A. Sender
B. Message
C. Sender & Message
D. None of the mentioned
Answer» D. None of the mentioned
10.

Which operation is used in encryption using IDEA?

A. Addition modulo 216
B. Bit wise XOR
C. Addition modulo 216 & Bit wise XOR
D. None of the mentioned
Answer» D. None of the mentioned
11.

The key size of DES is

A. 56 bits
B. 64 bits
C. 128 bits
D. 168 bits
Answer» B. 64 bits
12.

These three ciphers can operate of ______ of plaintext and cipher text.

A. 128 bit blocks
B. 64 bit blocks
C. 256 bit blocks
D. 156 bit blocks
Answer» C. 256 bit blocks
13.

Which block cipher has key length of 128 bits?

A. IDEA
B. CAST
C. IDEA & CAST
D. None of the mentioned
Answer» D. None of the mentioned
14.

PGP offers _____ block ciphers for message encryption.

A. Triple-DES
B. CAST
C. IDEA
D. All of the mentioned
Answer» E.
15.

Data compression includes

A. Removal of redundant character
B. Uniform distribution of characters
C. Removal of redundant character & Uniform distribution of characters
D. None of the mentioned
Answer» D. None of the mentioned
16.

For digital signatures private key cryptosystem is used.

A. True
B. False
Answer» C.
17.

Public key cryptosystem is used for the encryption of

A. Messages
B. Session key
C. Session key & Messages
D. None of the mentioned
Answer» C. Session key & Messages
18.

Pretty good privacy (PGP) security system uses

A. Public key cryptosystem
B. Private key cryptosystem
C. Public & Private key cryptosystem
D. None of the mentioned
Answer» D. None of the mentioned