Certified Information Systems Security Professional (CISSP) — Question 180

Which of the following is a weakness of the Data Encryption Standard (DES)?

Answer options

• A. Block encryption scheme
• B. Use of same key for encryption and decryption
• C. Publicly disclosed algorithm
• D. Inadequate key length

Correct answer: D

Explanation

The correct answer is D because DES has a key length of only 56 bits, making it vulnerable to brute-force attacks. Options A, B, and C describe characteristics of DES but do not represent weaknesses; for instance, the block encryption scheme and the use of the same key are standard practices in symmetric encryption.