Question

What type of cryptographic attack rendered Double DES (2DES) no more effective than standard DES encryption?

A. Man-in-the-middle attack
B. Meet-in-the-middle attack
C. Chosen ciphertext attack
D. Birthday attack

Answer 1

The Meet-in-the-middle attack rendered Double DES (2DES) no more effective than standard DES encryption by reducing the effective key size. This attack is a chosen plaintext attack where the attacker exploits the vulnerability of Double DES to a space-time tradeoff.

Step-by-step explanation:

The cryptographic attack that rendered Double DES (2DES) no more effective than standard DES encryption is the Meet-in-the-middle attack. The Meet-in-the-middle attack is a chosen plaintext attack where the attacker exploits the fact that Double DES is vulnerable to a space-time tradeoff.

In a Meet-in-the-middle attack, the attacker encrypts the plaintext with all possible encryption keys for the first encryption, and then decrypts the resulting ciphertext with all possible decryption keys for the second encryption. By comparing the intermediate results, the attacker can find a matching pair of keys, thus breaking the encryption.

As a result, Double DES is no more secure than standard DES encryption because the Meet-in-the-middle attack reduces the effective key size from 112 bits to 57 bits, which can be efficiently cracked with modern computing power.