In CEH v13 Module 14: Cryptography, Serpent is detailed as one of the finalists in the Advanced Encryption Standard (AES) competition, known for its strong security characteristics.
Key Features of Serpent:
128-bit block size, and key sizes of 128, 192, or 256 bits.
Uses 32 rounds of substitution and permutation.
Operates on four 32-bit words per block.
Employs 8 different S-boxes, each with a 4-bit input and 4-bit output.
Designed to provide high security and resistance against differential cryptanalysis.
Option Clarification:
A). TEA: Uses a Feistel structure with simple operations, but not 32 rounds with S-boxes.
B). CAST-128: Has 64-bit block size and fewer rounds.
C). RC5: Variable block and key sizes but doesn't use 32 rounds with fixed S-box design.
D). Serpent: Matches all given features.
Reference:
Module 14 - Symmetric Algorithms and AES Candidates
CEH eBook: AES Finalists - Serpent, Rijndael, RC6, Twofish