D334 Introduction to Cryptography - Set 3 - Part 2

Correct Answer: Caesar cipher

The Caesar cipher is a simple substitution cipher that shifts the letters of the plaintext by a fixed number of positions.

Correct Answer: CBC

Cipher Block Chaining (CBC) mode XORs each plaintext block with the previous ciphertext block before encryption, ensuring that identical plaintext blocks produce different ciphertexts.

Correct Answer: ECC

Elliptic Curve Cryptography (ECC) is based on the mathematical difficulty of solving discrete logarithms, making it secure for encryption and key exchange.

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

A hash function generates a fixed-length output (hash) from a variable-length input, ensuring data integrity without being reversible.

Correct Answer: RSA

RSA is widely used for creating digital signatures, ensuring message integrity and authenticity.

Correct Answer: It requires secure key distribution

The main disadvantage of symmetric encryption is the need for secure key distribution between parties, as both must use the same key.

Correct Answer: Cryptanalysis attack

A cryptanalysis attack involves manipulating the encryption algorithm to find weaknesses or patterns that can be exploited to break the encryption.

Correct Answer: CTR

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

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

Forward secrecy ensures that even if long-term keys are compromised, past communication sessions remain secure because session keys are not reused.

Correct Answer: Symmetric encryption

In symmetric encryption, the same key is used for both encryption and decryption, requiring secure key exchange between the parties.

Correct Answer: OCSP

The Online Certificate Status Protocol (OCSP) is used to check the validity of digital certificates in real-time, ensuring that they have not been revoked.

Correct Answer: To verify the identity of the sender and the integrity of the message

A digital signature verifies the identity of the sender and ensures that the message has not been tampered with during transmission.

Correct Answer: ECC

Elliptic Curve Cryptography (ECC) is commonly used in blockchain technologies for securing transactions due to its efficiency and smaller key sizes.

Correct Answer: Replay attack

In a replay attack, an attacker captures valid data transmissions and reuses them at a later time to gain unauthorized access.

Correct Answer: SHA-256

SHA-256 is a cryptographic hash algorithm that generates a fixed-length hash value, ensuring data integrity.

Correct Answer: An attacker intercepts and alters communications between two parties

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

Correct Answer: Asymmetric encryption

Asymmetric encryption uses different keys for encryption and decryption, typically a public key for encryption and a private key for decryption.

Correct Answer: To provide a unique value used only once to ensure data uniqueness

A nonce is a value used only once in encryption to ensure that the same plaintext encrypted multiple times results in different ciphertexts.

Correct Answer: It uses smaller key sizes for the same level of security as RSA

ECC provides equivalent security to RSA but with much smaller key sizes, making it more efficient in terms of computation and storage.

Correct Answer: ECB

In ECB mode, identical plaintext blocks produce identical ciphertext blocks, making it vulnerable to pattern analysis attacks.