ISC2 ISSAP Exam - Topic 3 Question 97 Discussion

Actual exam question for ISC2's ISSAP exam

Question #: 97
Topic #: 3

Which of the following encryption modes can make protocols without integrity protection even more susceptible to replay attacks, since each block gets decrypted in exactly the same way?

ACipher feedback mode

BCipher block chaining mode

COutput feedback mode

DElectronic codebook mode

Show Suggested Answer

Suggested Answer: D

by Vannessa at Mar 06, 2025, 04:09 AM

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Luann

3 months ago

Cipher block chaining can help with that, right?

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Malcom

3 months ago

Yup, ECB is a no-go for security!

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Ivan

3 months ago

Wait, are we sure about that? Seems too simple.

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Willodean

4 months ago

I agree, ECB is super weak for that reason.

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Gary

4 months ago

Definitely ECB mode! Each block is independent.

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Alecia

4 months ago

I’m a bit confused, but I remember that Output Feedback mode also has some vulnerabilities. Still, I lean towards ECB for this question.

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Billi

4 months ago

I recall practicing a question about encryption modes, and I think ECB was mentioned as being weak. It seems like the right choice here.

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Doyle

4 months ago

I'm not entirely sure, but I feel like Cipher Block Chaining mode is more secure against replay attacks since it uses chaining.

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Nieves

5 months ago

I think it might be Electronic Codebook mode because I remember it doesn't use an initialization vector, which could lead to patterns being repeated.

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Ludivina

5 months ago

This question is testing our understanding of how different encryption modes can impact security. I'll need to think carefully about the implications of each mode.

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Jules

5 months ago

Okay, let me carefully consider the details of each encryption mode. I want to make sure I select the right answer.

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Milly

5 months ago

Aha, I know the answer to this one! It's option B, cipher block chaining mode.

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Tyra

5 months ago

Hmm, I'm a bit unsure about this. I'll have to review my notes on encryption modes to figure this out.

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Johnathon

5 months ago

This one seems tricky, but I think I can work through it. Let me think this through step-by-step.

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Lashawnda

9 months ago

Wait, is it me or does this question sound like it's straight out of a spy movie? I feel like I should be wearing a tuxedo while answering this.

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Earleen

9 months ago

D definitely seems like the right answer. I can't believe I almost fell for that tricky wording in the question!

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Van

8 months ago

D) Electronic codebook mode

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Aliza

8 months ago

C) Output feedback mode

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Kate

9 months ago

B) Cipher block chaining mode

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Arlene

9 months ago

A) Cipher feedback mode

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Florinda

10 months ago

Ugh, these encryption modes can be so confusing. I'm just hoping for a multiple-choice miracle on this one.

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Muriel

8 months ago

D) Electronic codebook mode

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Kerry

8 months ago

C) Output feedback mode

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Ceola

8 months ago

B) Cipher block chaining mode

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Ahmed

9 months ago

A) Cipher feedback mode

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Beckie

10 months ago

Haha, I bet the exam writers were just waiting to trick us with that one. Good thing I studied hard for this!

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Fanny

9 months ago

D) Electronic codebook mode

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Murray

9 months ago

C) Output feedback mode

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Paulina

10 months ago

B) Cipher block chaining mode

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Nieves

10 months ago

A) Cipher feedback mode

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Gene

11 months ago

I agree with Jose, Electronic codebook mode makes protocols more susceptible to replay attacks.

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Nickolas

11 months ago

I think the answer is D. Electronic codebook mode, since it encrypts each block independently, making it vulnerable to replay attacks.

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Tamie

9 months ago

D) Electronic codebook mode

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Freida

10 months ago

C) Output feedback mode

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Armando

10 months ago

B) Cipher block chaining mode

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Peter

10 months ago

A) Cipher feedback mode

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Clay

11 months ago

I disagree, I believe the correct answer is B) Cipher block chaining mode.

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Jose

11 months ago

I think the answer is D) Electronic codebook mode.

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