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SSCP · Question #680

The Data Encryption Algorithm performs how many rounds of substitution and permutation?

The correct answer is B. 16. The Data Encryption Standard (DES), also known as the Data Encryption Algorithm (DEA), performs 16 rounds of substitution and permutation on the plaintext during encryption.

Submitted by ravi_2018· Apr 18, 2026Cryptography

Question

The Data Encryption Algorithm performs how many rounds of substitution and permutation?

Options

  • A4
  • B16
  • C54
  • D64

How the community answered

(25 responses)
  • B
    92% (23)
  • C
    4% (1)
  • D
    4% (1)

Why each option

The Data Encryption Standard (DES), also known as the Data Encryption Algorithm (DEA), performs 16 rounds of substitution and permutation on the plaintext during encryption.

A4

4 rounds is insufficient for the security requirements of DES and is not the standard number of rounds.

B16Correct

The Data Encryption Standard (DES), referred to as the Data Encryption Algorithm (DEA), is a block cipher that operates on 64-bit blocks of data. It performs a sequence of 16 identical rounds, with each round involving substitution (S-boxes) and permutation (P-boxes) operations, combined with a subkey derived from the main key.

C54

54 rounds is not the specified number of rounds for the DES algorithm.

D64

64 rounds is not the specified number of rounds for the DES algorithm; 64 is the block size in bits.

Concept tested: DES/DEA number of rounds

Topics

#DES#Data Encryption Algorithm#Symmetric Encryption#Block Cipher Rounds

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