CEH Practice Question: Advanced Topics: Wireless, Cloud, IoT, Cryptography

Answer analysis

Option-by-option breakdown

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

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  SHA-256

  Why it's wrong here

  SHA-256 is a cryptographic hash function, not an encryption algorithm. It produces a fixed-size 256-bit hash value (message digest) from arbitrary-length input data, primarily used for data integrity verification and digital signatures. Unlike encryption, hashing is a one-way process; it is computationally infeasible to reverse a hash to obtain the original plaintext, thus it cannot be used to encrypt and decrypt data for confidentiality.

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  Diffie-Hellman (DH)

  Why it's wrong here

  Diffie-Hellman (DH) is a foundational asymmetric key exchange protocol, not an encryption algorithm. It allows two parties to establish a shared secret key over an insecure channel, relying on the mathematical difficulty of computing discrete logarithms. While DH enables the secure *exchange* of keys for subsequent symmetric encryption, it does not perform encryption or decryption of message data itself, distinguishing it from an encryption algorithm. Its elliptic curve variant, ECDH, leverages ECC principles for key exchange.

• ✗

  Triple DES (3DES)

  Why it's wrong here

  Triple DES (3DES) is a symmetric-key block cipher, not an asymmetric algorithm. It applies the original DES algorithm three times to each data block, using either two or three distinct keys. Symmetric encryption algorithms utilize the same secret key for both encryption and decryption, requiring secure pre-sharing of this key between communicating parties. This fundamental characteristic makes 3DES unsuitable for scenarios requiring public/private key pairs, which is the defining feature of asymmetric cryptography.

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  Elliptic Curve Cryptography (ECC)

  Why this is correct

  Elliptic Curve Cryptography (ECC) is an asymmetric encryption algorithm that derives its security from the mathematical properties of elliptic curves over finite fields, specifically the difficulty of the Elliptic Curve Discrete Logarithm Problem (ECDLP). It provides a robust framework for public-key cryptography, including encryption, digital signatures, and key exchange. ECC is highly efficient, offering equivalent security to RSA with significantly smaller key sizes, making it particularly well-suited for resource-constrained environments like mobile devices.

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