Quick Answer
The correct answer is RSA, as it is a widely recognized asymmetric encryption algorithm. Unlike symmetric systems that share a single secret key, RSA uses a mathematically linked public and private key pair, relying on the computational difficulty of factoring large prime numbers to secure data and create digital signatures. On the Certified Ethical Hacker CEH exam, this distinction often appears in questions contrasting symmetric vs. asymmetric ciphers, with RSA and ECC being the two primary asymmetric algorithms you must know. A common trap is confusing RSA with AES or DES, which are symmetric; remember that any algorithm named after its inventors (Rivest–Shamir–Adleman) or using key pairs is asymmetric. For ECC, recall it achieves equivalent security with smaller keys than RSA, but both are asymmetric. A quick memory tip: “RSA = Really Secure Asymmetric” — the “A” in RSA stands for asymmetric in practice.
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 of the following cryptographic algorithms is classified as asymmetric?
RSA
RSA is an asymmetric cryptosystem using public/private key pairs.
3DES
Why wrong: 3DES is a symmetric encryption algorithm.
SHA-256
Why wrong: SHA-256 is a cryptographic hash function, not an encryption algorithm.
AES
Why wrong: AES is a symmetric block cipher.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
RSA
RSA (Rivest–Shamir–Adleman) is a public-key cryptosystem that uses a pair of keys (public and private) for encryption and digital signatures, making it an asymmetric algorithm. Unlike symmetric ciphers, RSA relies on the mathematical difficulty of factoring large prime numbers to secure communications.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
RSA
Why this is correct
RSA is an asymmetric cryptosystem using public/private key pairs.
Related concept
Read the scenario before looking for a memorised answer.
3DES
Why it's wrong here
3DES is a symmetric encryption algorithm.
SHA-256
Why it's wrong here
SHA-256 is a cryptographic hash function, not an encryption algorithm.
AES
Why it's wrong here
AES is a symmetric block cipher.
Common exam traps
The trap here is that candidates confuse 'asymmetric' with 'symmetric' algorithms or mistakenly classify hash functions (like SHA-256) as encryption, when in fact asymmetric algorithms always involve a key pair (public/private) and RSA is the classic example tested on the CEH exam.
Detailed technical explanation
RSA's security is based on the integer factorization problem; key generation involves selecting two large primes (typically 2048 bits or more in modern implementations) and computing the product n = p × q. In real-world scenarios, RSA is often used to encrypt symmetric session keys (e.g., for AES) in hybrid cryptosystems like TLS, because asymmetric encryption is computationally expensive for bulk data.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
A small business has 20 workstations on the 192.168.1.0/24 network and one public IP from its ISP. The router uses PAT (NAT overload) so all 20 devices share one public address using different source ports. NAT questions test whether you understand the four address terms and which direction each translation applies.
What to study next
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FAQ
Advanced Topics: Wireless, Cloud, IoT, Cryptography — This question tests Advanced Topics: Wireless, Cloud, IoT, Cryptography — Read the scenario before looking for a memorised answer..
The correct answer is: RSA — RSA (Rivest–Shamir–Adleman) is a public-key cryptosystem that uses a pair of keys (public and private) for encryption and digital signatures, making it an asymmetric algorithm. Unlike symmetric ciphers, RSA relies on the mathematical difficulty of factoring large prime numbers to secure communications.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Read the scenario before looking for a memorised answer.
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Same concept, more angles
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 asymmetric encryption algorithms? (Choose two.)
easyWhy B: RSA and ECC are asymmetric algorithms. AES and 3DES are symmetric. SHA-256 is a hash function.
Variation 2. Which of the following cryptographic algorithms is classified as asymmetric?
easyWhy D: RSA is an asymmetric algorithm using a public/private key pair. AES, 3DES, and RC4 are symmetric algorithms.
Variation 3. Which of the following cryptographic algorithms is classified as asymmetric?
easyWhy C: Asymmetric cryptography uses key pairs (public and private). RSA is a well-known asymmetric algorithm. AES, 3DES, and RC4 are symmetric algorithms.
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Last reviewed: Jun 24, 2026
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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