Question 271 of 1,000

Cryptography →mediumMultiple ChoiceObjective-mapped

SSCP Cryptography Practice Question

Q: How is Cryptography tested on the SSCP exam?

Cryptography — This question tests Cryptography — Read the scenario before looking for a memorised answer..

Q: What is the correct answer to this Cryptography SSCP question?

The correct answer is: RC4 — RC4 is a stream cipher that has known vulnerabilities, including the BEAST attack (Browser Exploit Against SSL/TLS), which exploits weaknesses in RC4's key scheduling and allows plaintext recovery. Since the organization wants to avoid stream ciphers due to such vulnerabilities, RC4 should be avoided.

Q: Why do candidates get Cryptography questions wrong on the SSCP exam?

Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.

This SSCP practice question tests your understanding of cryptography. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.

An organization is moving away from legacy encryption and wants to avoid stream ciphers due to known vulnerabilities. Which of the following algorithms should be avoided because it is a stream cipher with known weaknesses like the BEAST attack?

A
RC4
RC4 is the deprecated stream cipher.
B
3DES
Why wrong: 3DES is a block cipher.
C
AES-GCM
Why wrong: AES-GCM is a block cipher mode, not a stream cipher.
D
ChaCha20
Why wrong: ChaCha20 is a modern stream cipher considered secure.

Full breakdown with real-world context →

Answer choices

Why each option matters

Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.

Correct answer & explanation

✓

RC4

RC4 is a stream cipher that has known vulnerabilities, including the BEAST attack (Browser Exploit Against SSL/TLS), which exploits weaknesses in RC4's key scheduling and allows plaintext recovery. Since the organization wants to avoid stream ciphers due to such vulnerabilities, RC4 should be avoided.

Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

✓
RC4
Why this is correct
RC4 is the deprecated stream cipher.
Related concept
Read the scenario before looking for a memorised answer.
✗
3DES
Why it's wrong here
3DES is a block cipher.
✗
AES-GCM
Why it's wrong here
AES-GCM is a block cipher mode, not a stream cipher.
✗
ChaCha20
Why it's wrong here
ChaCha20 is a modern stream cipher considered secure.

Common exam traps

Common exam trap: answer the scenario, not the keyword

The trap here is that candidates may assume all stream ciphers are equally vulnerable, but ChaCha20 is a modern, secure stream cipher, while RC4 is the specific one with known weaknesses like BEAST.

Detailed technical explanation

How to think about this question

The BEAST attack specifically targets TLS 1.0 and earlier by exploiting predictable initialization vectors (IVs) in CBC mode, but it was also used to weaken RC4 by leveraging biases in its output. RC4's key scheduling algorithm (KSA) and pseudo-random generation algorithm (PRGA) produce statistical biases that allow plaintext recovery after observing many ciphertexts, as documented in RFC 7465, which prohibits RC4 in TLS. In real-world scenarios, legacy systems still using RC4 in SSL/TLS are vulnerable to such attacks, making migration to AES-GCM or ChaCha20 critical.

KKey Concepts to Remember

Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.

TExam Day Tips

Watch for words such as best, first, most likely and least administrative effort.
Review why wrong options are wrong, not only why the correct option is correct.

Key takeaway

Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.

Real-world example

How this comes up in practice

A developer is choosing between AES-256 (symmetric) and RSA-2048 (asymmetric) for encrypting a large file that will be sent to a partner. Symmetric encryption is fast but requires key exchange; asymmetric is slower but solves the key distribution problem. A hybrid approach — encrypt the file with AES, encrypt the AES key with RSA — is standard. Questions like this test whether you understand when each approach applies.

Quick reference

Symmetric Encryption Algorithm Comparison

Algorithm	Key Size	Block Size	Status	Notes
AES-128	128-bit	128-bit	Current standard	NIST approved; WPA3, TLS
AES-256	256-bit	128-bit	Current standard	Preferred for sensitive / govt data
3DES	112-bit effective	64-bit	Deprecated (2023)	Replaced by AES
DES	56-bit	64-bit	Broken	Cracked in < 24 h; never deploy
ChaCha20	256-bit	Stream cipher	Current	TLS 1.3, WireGuard

What to study next

Got this wrong? Here's your next step.

Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.

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FAQ

Questions learners often ask

What does this SSCP question test?

Cryptography — This question tests Cryptography — Read the scenario before looking for a memorised answer..

What is the correct answer to this question?

The correct answer is: RC4 — RC4 is a stream cipher that has known vulnerabilities, including the BEAST attack (Browser Exploit Against SSL/TLS), which exploits weaknesses in RC4's key scheduling and allows plaintext recovery. Since the organization wants to avoid stream ciphers due to such vulnerabilities, RC4 should be avoided.

What should I do if I get this SSCP question wrong?

Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.

What is the key concept behind this question?

Read the scenario before looking for a memorised answer.

About these practice questions

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Last reviewed: Jul 4, 2026

Question Discussion

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This SSCP practice question is part of Courseiva's free ISC2 certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the SSCP exam.