Question

In the DES algorithm, the round input is 32 bits, which is expanded to 48 bits via:

• A. Scaling of the existing bits
• B. Duplication of the existing bits
• C. Addition of zeros
• D. Addition of ones

Hint:

In DES, bit duplication ensures compatibility with the key size while preserving the original structure of the data.

Answer 1

The Correct Option is B

Within the Data Encryption Standard (DES) algorithm, a 32-bit block is expanded to 48 bits by duplicating specific bits based on a predefined expansion table. This expansion is necessary to align the data block with the 48-bit key used in each DES round.