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Cryptography Objective Questions and Answers - Set 2
This cryptography quiz contains carefully curated objective questions with correct answers and clear explanations. It is designed for developers, security learners, and interview preparation, covering modern encryption, hashing, authentication, and security best practices. This is part 2 of the series.
Practice Cryptography MCQs with Detailed Explanations
Answer at least 12 questions to submit and verify answers.
16 Which algorithm is vulnerable to length extension attacks? Hard
Correct answer:
MD5
MD5 and some SHA algorithms are vulnerable to length extension attacks if not used correctly.
17 What is the key size of AES-256? Easy
Correct answer:
256 bits
AES-256 uses a 256-bit encryption key, offering a high level of security.
18 Which algorithm is commonly used for key exchange? Medium
Correct answer:
Diffie-Hellman
Diffie-Hellman enables secure key exchange over an insecure channel.
19 What does PBKDF2 stand for? Medium
Correct answer:
Password-Based Key Derivation Function 2
PBKDF2 is a password-based key derivation function used to securely hash passwords.
20 Which encryption mode is NOT recommended due to pattern leakage? Medium
Correct answer:
ECB
ECB mode leaks patterns and should never be used for secure encryption.
21 Which algorithm uses elliptic curves? Easy
Correct answer:
ECC
ECC uses elliptic curve mathematics to provide strong security with smaller key sizes.
22 What is the main use of Shamir’s Secret Sharing? Medium
Correct answer:
Split secrets into shares
Shamir’s Secret Sharing splits a secret into multiple parts so that only a subset is required to reconstruct it. Try it using the Shamir’s Secret Sharing Tool.
23 Which algorithm is designed to be fast in software? Medium
Correct answer:
ChaCha20
ChaCha20 is optimized for speed and security in software environments.
24 What does a CSR contain? Easy
Correct answer:
Public key and identity info
A Certificate Signing Request contains a public key and identifying information. You can generate one using the Generate CSR Online Tool.
25 Which hashing algorithm produces a 256-bit output? Easy
Correct answer:
SHA-256
SHA-256 produces a 256-bit hash and is widely used for integrity verification.
26 What is the purpose of Poly1305? Medium
Correct answer:
Message authentication
Poly1305 is a MAC algorithm used for message authentication. You can try it using the Poly1305 MAC Generator.
27 Which cryptographic primitive ensures confidentiality? Easy
Correct answer:
Encryption
Encryption ensures confidentiality by preventing unauthorized access to data.
28 Which algorithm is commonly used for file encryption? Easy
Correct answer:
AES
AES is commonly used for file encryption. Try encrypting files using the File Encrypt Decrypt Tool.
29 What is the main drawback of DES? Medium
Correct answer:
Short key length
DES uses a 56-bit key, which is too short by modern security standards.
30 Which algorithm is recommended for modern TLS? Medium
Correct answer:
AES-GCM
AES-GCM is recommended for modern TLS due to its security and performance.