Your organization still uses single DES for encrypting backup tapes. A compliance audit flags this as a risk. Which is the most accurate reason why single DES is considered insecure today?

Its S-boxes are known to have mathematical backdoors inserted by the NSA.

Its block size of 64 bits is too small for modern data volumes.

Its 16 rounds are insufficient to prevent differential cryptanalysis in practice.

Its 56-bit key space is small enough to be exhaustively searched with modern hardware.

EC-CouncilCertified Encryption Specialist

Domain 2Objective 1

Feistel Networks, DES, 3DES, and AES ECES Practice Questions (Page 9)

Part of the Symmetric Cryptography and Hashing domain, which makes up ~17% of our current practice bank. EC-Council does not publish an official question count, but from its 120-minute exam (~50–80 total, ~9–14 in this domain), expect 3–5 from this objective — we provide 51 practice questions to prepare you well beyond it. (estimate)

51questions here

11free pages

12concepts

Questions 41–45

41foundation · easy
How many round keys are generated for AES-256?
Select an answer first
42foundation · easy
In AES, which transformation performs byte-by-byte substitution using an S-box?
Select an answer first
43application · easy
You are configuring a new encryption module that must support AES-256. The module's documentation mentions a 128-bit block size and a state array. How many rounds will AES-256 perform?
Select an answer first
44foundation · easy
What is the effective key length of two-key 3DES (using K1 and K2)?
Select an answer first
45application · medium
Your organization still uses single DES for encrypting backup tapes. A compliance audit flags this as a risk. Which is the most accurate reason why single DES is considered insecure today?
Select an answer first

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Feistel Networks, DES, 3DES, and AES ECES Practice Questions (Page 9)

Questions 41–45

How many round keys are generated for AES-256?

In AES, which transformation performs byte-by-byte substitution using an S-box?

You are configuring a new encryption module that must support AES-256. The module's documentation mentions a 128-bit block size and a state array. How many rounds will AES-256 perform?

What is the effective key length of two-key 3DES (using K1 and K2)?

Your organization still uses single DES for encrypting backup tapes. A compliance audit flags this as a risk. Which is the most accurate reason why single DES is considered insecure today?

Keep studying — Symmetric Cryptography and Hashing