D334 Introduction to Cryptography - Set 2 - Part 1

Correct Answer: RSA

RSA encryption is based on the mathematical challenge of factoring large prime numbers, which makes it secure but computationally intensive.

Correct Answer: Playfair

The Playfair cipher uses a 5x5 grid of letters for encryption and decryption, where plaintext letters are replaced based on their position in the matrix.

Correct Answer: It encrypts data one bit or byte at a time

Stream ciphers encrypt data one bit or byte at a time, making them faster and suitable for real-time data transmission.

Correct Answer: ECB

ECB mode does not use initialization vectors, which means identical plaintext blocks will produce identical ciphertext blocks, making it vulnerable to pattern analysis.

Correct Answer: AES

AES encryption is used in WPA2 to secure Wi-Fi networks because it provides strong encryption and is resistant to known vulnerabilities.

Correct Answer: An attacker tries to guess the encryption key by testing all possible combinations

In a brute-force attack, the attacker systematically tests every possible key combination until the correct key is found.

Correct Answer: Homomorphic encryption

Homomorphic encryption allows for computations to be performed on encrypted data, making it useful in scenarios where data privacy must be maintained during processing.

Correct Answer: SHA-1

SHA-1 produces a 160-bit hash output, although it is now considered weak due to vulnerability to collision attacks.

Correct Answer: It uses smaller keys for the same level of security

ECC offers the same security as RSA but with much smaller key sizes, making it more efficient in terms of computational overhead and storage requirements.

Correct Answer: Caesar

The Caesar cipher is a simple substitution cipher that shifts each letter by a fixed number of positions, typically by three.

Correct Answer: AES

AES is a block cipher, meaning it encrypts data in fixed-size blocks, as opposed to stream ciphers like RC4 that encrypt data one bit or byte at a time.

Correct Answer: CTR

CTR mode allows for parallel processing because each block is encrypted independently, improving performance in high-speed systems.

Correct Answer: RSA

RSA is a public key encryption algorithm, while AES, DES, and RC5 are symmetric key algorithms.

Correct Answer: AES

AES is a symmetric encryption algorithm, meaning the same key is used for both encryption and decryption.

Correct Answer: Identical plaintext blocks produce identical ciphertext blocks

ECB mode is vulnerable because identical plaintext blocks always result in identical ciphertext blocks, making it susceptible to pattern analysis.

Correct Answer: To issue and manage digital certificates

A Certificate Authority is responsible for issuing, validating, and managing digital certificates used to verify the identity of entities in a public key infrastructure.

Correct Answer: Replay attack

In a replay attack, an attacker captures a valid data transmission and replays it at a later time to gain unauthorized access.

Correct Answer: A different key is used for each message, and it is only used once

A one-time pad uses a key that is randomly generated and used only once, making it theoretically unbreakable if the key is truly random and kept secret.

Correct Answer: Diffie-Hellman

Diffie-Hellman is a key exchange algorithm based on the difficulty of solving discrete logarithms, providing a way to securely exchange cryptographic keys over an insecure channel.

Correct Answer: SHA-256

SHA-256 is a cryptographic hash function that produces a 256-bit hash value, offering stronger security compared to MD5 and SHA-1.