Which of the following encryption algorithms are based on block ciphers?

The correct answer is B. Twofish C. Rijndael D. RC5. Twofish (B), Rijndael (C), and RC5 (D) are all block ciphers - they operate on fixed-size chunks of data (blocks) using a symmetric key, encrypting the entire block at once. Rijndael is the algorithm standardized as AES, Twofish was a finalist in the AES competition, and RC5 is…

Infrastructure Security

Question

Options

ARC4
BTwofish
CRijndael
DRC5

How the community answered

(52 responses)

A
10% (5)
B
90% (47)

Explanation

Twofish (B), Rijndael (C), and RC5 (D) are all block ciphers - they operate on fixed-size chunks of data (blocks) using a symmetric key, encrypting the entire block at once. Rijndael is the algorithm standardized as AES, Twofish was a finalist in the AES competition, and RC5 is Ron Rivest's configurable block cipher with variable block size and round count. RC4 (A) is the distractor - it is a stream cipher, meaning it encrypts data one byte at a time by generating a pseudorandom keystream, making it fundamentally different in design.

Memory tip: RC4's "stream" nature is in the name - the "4" looks like nothing special, but remember "RC4 = flow like a 4-lane stream." Anything with "fish" (Twofish, Blowfish) and Rijndael/AES are always block ciphers.

Topics

#Block cipher encryption#Rijndael (AES)#Twofish#RC4 stream cipher

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