CEH Practice Question: Advanced Topics: Wireless, Cloud, IoT, Cryptography
Which of the following cryptographic algorithms is classified as asymmetric?
⚠ Common exam trap
It's easy for candidates to 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.
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
✓
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.
Answer analysis
Option-by-option breakdown
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 correctly classified as an asymmetric cryptographic algorithm because it utilizes a distinct public key for encryption and a corresponding private key for decryption. This fundamental separation of keys allows for secure communication without prior shared secrets, enabling functions like digital signatures and secure key exchange. Its security relies on the computational difficulty of factoring large prime numbers, making it suitable for establishing secure channels.
- ✗
3DES
Why it's wrong here
Triple DES (3DES) is a symmetric block cipher, meaning it employs the identical secret key for both encrypting and decrypting data. It operates by applying the Data Encryption Standard (DES) algorithm three times to each data block, enhancing its security compared to single DES. However, its symmetric nature necessitates secure key distribution and management among communicating parties, and it is slower than modern alternatives like AES.
- ✗
SHA-256
Why it's wrong here
SHA-256 is a cryptographic hash function, not an encryption algorithm, designed to produce a fixed-size output (256 bits) from arbitrary-length input data. Its primary purpose is to ensure data integrity and authenticity by creating a unique digital fingerprint, not to conceal information. Unlike encryption, hashing is a one-way process, making it irreversible and therefore unsuitable for providing confidentiality.
- ✗
AES
Why it's wrong here
The Advanced Encryption Standard (AES) is a modern, highly efficient symmetric block cipher widely adopted for securing sensitive data. As a symmetric algorithm, it employs the same secret key for both encryption and decryption operations, making secure key management a critical security consideration. AES processes data in fixed-size blocks and offers robust confidentiality, but it does not inherently provide non-repudiation or authentication.
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 |
Go deeper
Related to this question
About these practice questions
One of 870 original CEH practice questions on Courseiva, each with a full explanation and wrong-answer analysis — not exam dumps or protected exam content. Learn why practice questions differ from exam dumps →
Same concept, more angles
3 more ways this is tested on CEH
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.)
easy- A.3DES
- ✓ B.ECC
- C.SHA-256
- ✓ D.RSA
- E.AES
Why 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?
easy- A.RC4
- B.3DES
- C.AES
- ✓ D.RSA
Why 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?
easy- A.RC4
- B.3DES
- ✓ C.RSA
- D.AES
Why C: Asymmetric cryptography uses key pairs (public and private). RSA is a well-known asymmetric algorithm. AES, 3DES, and RC4 are symmetric algorithms.
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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.