D334 Introduction to Cryptography - Set 5 - Part 1

Correct Answer: ECB

ECB (Electronic Codebook) mode is considered insecure because identical plaintext blocks result in identical ciphertext blocks, making it vulnerable to pattern analysis attacks.

Correct Answer: Cryptanalysis attack

A cryptanalysis attack attempts to recover plaintext or encryption keys by analyzing the ciphertext and using various techniques without needing to know the key.

Correct Answer: AES

AES is commonly used in full disk encryption due to its strong security and efficiency.

Correct Answer: ECC

Elliptic Curve Cryptography (ECC) relies on the difficulty of solving discrete logarithms, which is what provides its security.

Correct Answer: Transposition cipher

A transposition cipher rearranges the characters of the plaintext, while a substitution cipher changes the characters to other symbols or letters.

Correct Answer: Diffie-Hellman

Diffie-Hellman is used to securely establish a shared secret between two parties over an insecure channel, such as the internet.

Correct Answer: An attacker attempts to modify or alter the communications between two parties

An active attack involves modifying, intercepting, or altering the communications between two parties, whereas a passive attack involves eavesdropping without altering data.

Correct Answer: 192 bits

AES-192 uses a 192-bit key for encryption, providing a higher level of security than AES-128.

Correct Answer: RSA

RSA is commonly used for secure key exchange in PKI due to its use of public and private keys.

Correct Answer: Hashing

Hashing is used to ensure data integrity by generating a fixed-length hash value that can be compared to the original data to check for any changes.

Correct Answer: Brute-force attack

A brute-force attack involves trying all possible combinations of keys until the correct key is found.

Correct Answer: It uses different keys for encryption and decryption

Asymmetric encryption uses a public key for encryption and a private key for decryption, making it more secure for key exchange.

Correct Answer: ECC uses smaller key sizes for equivalent security

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

Correct Answer: CBC

Cipher Block Chaining (CBC) mode uses an initialization vector and chains each block to the previous one, making it more secure than ECB mode.

Correct Answer: It generates a fixed-length output from a variable-length input

A cryptographic hash function generates a fixed-length output, called a hash, from a variable-length input and is used to ensure data integrity.

Correct Answer: CTR

Counter (CTR) mode allows for parallel processing of blocks because each block is encrypted independently, improving performance in high-speed environments.

Correct Answer: It uses a small key size

DES uses a small key size of 56 bits, which makes it vulnerable to brute-force attacks.

Correct Answer: Man-in-the-middle attack

In a man-in-the-middle attack, the attacker intercepts and potentially alters the communication between two parties without their knowledge.

Correct Answer: It ensures that past sessions remain secure even if long-term keys are compromised

Perfect forward secrecy ensures that even if long-term encryption keys are compromised, previous session keys remain secure.

Correct Answer: It verifies the identity of the sender and the integrity of the message

A digital signature is used to verify the sender's identity and ensure that the message has not been tampered with.