Encryption and Decryption: Master the Art of Data Protection

Question 1

Which of these algorithms is a symmetric block cipher with a 128-bit block size and a 256-bit key size?

Accepted Answer

AES

Answer

DES

Answer

RSA

Answer

ECC

Question 2

Which cryptographic hash function generates a unique, fixed-length digest from an input of any length?

Accepted Answer

SHA-256

Answer

AES

Answer

RSA

Answer

MD5

Question 3

Which of the following is NOT a primary objective of encryption?

Accepted Answer

Availability

Answer

Confidentiality

Answer

Integrity

Answer

Non-repudiation

Question 4

What type of encryption algorithm encrypts data in fixed-size blocks?

Accepted Answer

Block cipher

Answer

Stream cipher

Answer

Hash function

Answer

One-time pad

Question 5

What is the primary function of a key exchange protocol?

Accepted Answer

To establish shared cryptographic keys securely

Answer

To encrypt data using a predefined key

Answer

To generate random keys for encryption

Answer

To verify the identities of communicating parties

Question 6

Which of the following is a commonly used symmetric encryption algorithm?

Accepted Answer

AES

Answer

RSA

Answer

SHA-256

Answer

Diffie-Hellman

Question 7

What is the primary distinction between block ciphers and stream ciphers?

Accepted Answer

Block ciphers operate on fixed-size blocks, while stream ciphers operate on continuous data streams

Answer

Stream ciphers are faster than block ciphers

Answer

Block ciphers provide stronger security than stream ciphers

Answer

Stream ciphers are simpler to implement than block ciphers

Question 8

What is the primary purpose of a hash function in the context of cryptography?

Accepted Answer

To create a fixed-length digest from input data

Answer

To encrypt data using a digital key

Answer

To exchange cryptographic keys securely

Answer

To verify the integrity of data

Question 9

What is the primary purpose of a digital certificate in public-key cryptography?

Accepted Answer

To authenticate the identity of a public key owner

Answer

To encrypt sensitive data

Answer

To generate cryptographic keys

Answer

To establish a secure communication channel

Question 10

Which of these algorithms uses separate keys for encryption and decryption?

Accepted Answer

Rivest-Shamir-Adleman (RSA)

Answer

Advanced Encryption Standard (AES)

Answer

Data Encryption Standard (DES)

Answer

Secure Hash Algorithm 256 (SHA-256)

Question 11

In a secure network communication, Alice encrypts a message using Bob's public key. What does this ensure?

Accepted Answer

Only Bob can decrypt the message

Answer

Only Alice can encrypt the message

Answer

A symmetric key is used for encryption

Answer

The message is sent over a secure channel

Question 12

Which of the following is NOT a type of encryption algorithm?

Accepted Answer

Encryption protocol

Answer

Stream cipher

Answer

Block cipher

Answer

Asymmetric cipher

Question 13

Which of the following algorithms is commonly used for symmetric encryption?

Accepted Answer

DES

Answer

RSA

Answer

ECC

Answer

SHA-256

Question 14

Which of the following is NOT a primary benefit of using encryption in network communication?

Accepted Answer

Enhancing network performance

Answer

Preserving data confidentiality

Answer

Ensuring data integrity

Answer

Preventing unauthorized access to data

Question 15

What is the main purpose of a cryptographic algorithm?

Accepted Answer

To securely convert data to a protected format

Answer

To manage and generate encryption keys

Answer

To transmit encrypted data efficiently

Answer

To provide secure storage for encryption techniques

Question 16

What is the distinction between a symmetric-key and an asymmetric-key encryption algorithm?

Accepted Answer

Symmetric-key encryption employs a single key for both encryption and decryption, unlike asymmetric-key encryption, which uses unique keys for each purpose.

Answer

Asymmetric-key algorithms are inherently faster than symmetric-key algorithms.

Answer

Symmetric-key encryption offers superior security compared to asymmetric-key algorithms.

Answer

Asymmetric-key encryption is exclusively used for digital signatures.

Question 17

What is the primary function of a hash function in cryptography?

Accepted Answer

To generate a unique digital fingerprint for data

Answer

To encrypt data using symmetric keys

Answer

To create encryption keys

Answer

To decrypt data using asymmetric keys

Question 18

What is the fundamental difference between a digital signature and an encryption key?

Accepted Answer

A digital signature authenticates a message, while an encryption key encrypts and decrypts data.

Answer

Digital signatures are significantly longer than encryption keys.

Answer

Digital signatures can encrypt data, and encryption keys can create digital signatures.

Answer

Digital signatures and encryption keys are functionally equivalent.

Question 19

Which of the following is considered poor practice in key management?

Accepted Answer

Use of weak keys

Answer

Secure key storage

Answer

Regular key rotation

Answer

Revocation of compromised keys

Question 20

What is the purpose of a certificate authority (CA) within a public key infrastructure (PKI)?

Accepted Answer

Issuance of digital certificates

Answer

Management of encryption keys

Answer

Data encryption

Answer

Data decryption

Question 21

Which key management technique is used to securely share encryption keys with authorized parties?

Accepted Answer

Key exchange

Answer

Password hashing

Answer

Certificate management

Answer

Public-key encryption

Question 22

Which encryption algorithm is commonly used for secure communication over the internet?

Accepted Answer

TLS/SSL

Answer

Vigenere Cipher

Answer

ROT13

Answer

Caesar Cipher

Question 23

What is the primary function of a digital signature in encryption?

Accepted Answer

Authentication and non-repudiation

Answer

Data encryption

Answer

Data compression

Answer

Error detection

Question 24

What is the key difference between symmetric and asymmetric encryption?

Accepted Answer

Symmetric encryption uses the same key for both encryption and decryption, while asymmetric encryption uses separate keys.

Answer

Symmetric encryption is used for data at rest, while asymmetric is used for data in transit.

Answer

Symmetric encryption is faster, while asymmetric encryption is more secure.

Answer

Symmetric encryption is easier to implement, while asymmetric encryption is more complex.

Question 25

Which of the following is NOT a recommended key management practice?

Accepted Answer

Using the same key for all communications.

Answer

Regular key rotation

Answer

Key revocation

Answer

Secure key storage

Question 26

In a public-key infrastructure (PKI), what is the primary role of a certificate authority (CA)?

Accepted Answer

Issuing and managing digital certificates

Answer

Encrypting data using public keys

Answer

Deciphering encrypted messages using private keys

Answer

Storing and retrieving cryptographic keys

Question 27

Which encryption standard is commonly used for wireless communication?

Accepted Answer

WPA2/3

Answer

DES

Answer

AES

Answer

RSA

Question 28

What is the primary purpose of a hash function in cryptography?

Accepted Answer

Generating a unique fingerprint of data for integrity verification.

Answer

Compressing data for efficient storage

Answer

Encrypting data for confidentiality

Answer

Generating a random key for encryption

Question 29

A network administrator implements a VPN to secure remote access. Which encryption method is typically used in VPNs?

Accepted Answer

IPsec

Answer

Caesar Cipher

Answer

RSA

Answer

DES

Question 30

Which of the following is NOT a benefit of encryption?

Accepted Answer

Increased data transmission speed

Answer

Authentication

Answer

Confidentiality

Answer

Integrity

Question 31

What is the process of converting plaintext into ciphertext called?

Accepted Answer

Encryption

Answer

Hashing

Answer

Encoding

Answer

Decryption