The answer is the birthday attack, preimage attack, and collision attack. These three cryptanalysis attacks on hash functions exploit fundamental weaknesses in how hashes map data: the birthday attack leverages the birthday paradox to find any two inputs producing the same hash output, a preimage attack reverses a given hash to discover an original input, and a collision attack actively seeks two distinct inputs that yield an identical hash. On the Certified Ethical Hacker CEH exam, this topic tests your understanding of hash integrity and why algorithms like SHA-1 are deprecated due to collision vulnerabilities. A common trap is confusing dictionary attacks—which are password guessing methods—with pure cryptanalysis, or assuming man-in-the-middle attacks target hash functions directly. To remember the trio, think of the three C’s: Collision, Birthday (a type of collision), and Preimage—each breaks a different promise of cryptographic hashing.
CEH Practice Question: Advanced Topics: Wireless, Cloud, IoT, Cryptography
This CEH practice question tests your understanding of advanced topics: wireless, cloud, iot, 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.
Which THREE of the following are cryptanalysis attacks that target hash functions? (Choose three.)
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Preimage attack
Birthday attack exploits hash collisions, preimage attack finds an input that hashes to a given output, and collision attack finds two inputs with same hash. Man-in-the-middle is not specific to hash functions, and dictionary attack is a password cracking technique, not pure cryptanalysis.
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.
✗
Man-in-the-middle attack
Why it's wrong here
MITM is a general attack on communications, not specific to hash functions.
✓
Preimage attack
Why this is correct
Preimage attack finds an input that hashes to a specific hash value.
Related concept
Read the scenario before looking for a memorised answer.
✓
Collision attack
Why this is correct
Collision attack finds two distinct inputs that produce the same hash.
Related concept
Read the scenario before looking for a memorised answer.
✓
Birthday attack
Why this is correct
Birthday attack uses probability to find collisions in hash functions.
Related concept
Read the scenario before looking for a memorised answer.
✗
Dictionary attack
Why it's wrong here
Dictionary attack is a brute-force method using wordlists, not a cryptanalytic attack on hash functions.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Many certification questions include familiar terms but test a specific constraint. Read the exact wording before choosing an answer that is generally true but wrong for this case.
Detailed technical explanation
How to think about this question
This question should be treated as a scenario, not a definition check. Identify the problem, the constraint and the best action. Then compare each option against those facts.
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.
Use explanations to understand the rule behind the answer.
TExam Day Tips
→Underline the problem statement mentally.
→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 practitioner preparing for the CEH exam encounters this exact type of scenario on the job. The correct answer here is not the most general option — it is the best answer for the specific constraint described. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Real exam questions reward reading the full scenario before eliminating options, because the constraint defines which answer fits.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this CEH question in full detail.
Identify which CEH exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
Advanced Topics: Wireless, Cloud, IoT, Cryptography — This question tests Advanced Topics: Wireless, Cloud, IoT, Cryptography — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Preimage attack — Birthday attack exploits hash collisions, preimage attack finds an input that hashes to a given output, and collision attack finds two inputs with same hash. Man-in-the-middle is not specific to hash functions, and dictionary attack is a password cracking technique, not pure cryptanalysis.
What should I do if I get this CEH question wrong?
Identify which CEH exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. Which TWO of the following are valid cryptanalytic attacks?
medium
A.SQL injection
✓ B.Replay attack
C.Downgrade attack
D.Cross-site scripting (XSS)
✓ E.Birthday attack
Why B: Birthday attack exploits hash collisions; replay attack reuses captured data. Downgrade attack forces weaker protocol (not cryptanalytic per se, but relevant). SQL injection and XSS are web application attacks, not cryptanalytic.
Variation 2. Which THREE of the following attacks target cryptographic weaknesses?
hard
✓ A.Downgrade attack
✓ B.Replay attack
C.Cross-site scripting
✓ D.Birthday attack
E.SQL injection
Why A: A downgrade attack is correct because it forces a system to use a weaker, less secure cryptographic protocol or algorithm (e.g., forcing TLS 1.2 down to SSL 3.0 or using export-grade ciphers). This exploits the cryptographic weakness of the older protocol, making it easier for an attacker to decrypt or manipulate the communication. The attack directly targets the cryptographic strength of the negotiated security parameters.
Last reviewed: Jun 21, 2026
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This CEH practice question is part of Courseiva's free EC-Council 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 CEH exam.
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