Pete works as a Network Security Officer for Gentech Inc. He wants to encrypt his network traffic. The specific requirement for the encryption algorithm is that it must be a symmetric key block…

Question

Options

• AIDEA
• BPGP
• CDES
• DAES

• A
  4% (2)
• B
  14% (7)
• C
  78% (39)
• D
  4% (2)

Explanation

DES (Data Encryption Standard) is a symmetric key block cipher that encrypts data in 64-bit blocks using a 56-bit key, directly satisfying both requirements in the question. PGP (B) is eliminated immediately because it is a hybrid encryption system that combines both symmetric and asymmetric techniques for key exchange and data encryption - not a pure symmetric key algorithm. IDEA (A) is actually also a symmetric block cipher (128-bit key, 64-bit blocks), and AES (D) is also a symmetric block cipher - making this a poorly worded question where C, A, and D are technically all valid; however, exam banks for older certifications (such as early CEH versions) treat DES as the canonical answer because it was the first widely standardized symmetric block cipher and is most directly associated with that definition in foundational coursework.

Memory tip: Think "DES = the original symmetric block cipher standard" - the word Standard in its name signals it was formally standardized as the block cipher, making it the go-to exam answer when a question asks about a "symmetric key block cipher" without additional qualifiers. If you see AES on a newer exam version, that would also be correct - flag questions like this as potentially outdated.

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