Eccouncil 212-81 Exam - Topic 8 Question 64 Discussion

Actual exam question for Eccouncil's 212-81 exam

Question #: 64
Topic #: 8

[All 212-81 Questions]

A _____ is a function that takes a variable-size input m and returns a fixed-size string.

AFeistel

BAsymmetric cipher

CSymmetric cipher

DHash

Show Suggested Answer

Suggested Answer: D

Hash

https://en.wikipedia.org/wiki/Hash_function

A hash function is any function that can be used to map data of arbitrary size to fixed-size values.

by Mozell at Nov 23, 2025, 10:36 PM

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Tatum

5 months ago

Yeah, D) Hash is the best choice. It’s straightforward!

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Jospeh

5 months ago

I’m leaning towards D too. Symmetric and asymmetric ciphers don’t match.

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Cordelia

5 months ago

Definitely D) Hash. It’s all about that fixed-size string.

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Audrie

5 months ago

I feel like A) Feistel could be a trick option, but it’s not the right fit.

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Reena

5 months ago

Hash functions are super important for data integrity!

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Ettie

6 months ago

I thought it was an asymmetric cipher at first.

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Nada

6 months ago

Wait, isn't a Feistel structure also related to this?

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Chau

6 months ago

Agreed, D is the right answer!

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Dacia

7 months ago

D) Hash, no doubt. Although, I'm pretty sure a Feistel cipher is just a fancy way of saying "the secret ingredient is cheese."

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Louann

7 months ago

D) Hash, for sure. Although, I'm still trying to figure out who this "Feistel" guy is and why he's got a function named after him.

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Felix

7 months ago

D) Hash, easy peasy. Now, if only I could remember how to pronounce "Feistel" without sounding like a cat with a hairball.

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Bette

7 months ago

Definitely D. I always get my hashes and ciphers mixed up, but this one's a no-brainer.

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Julio

7 months ago

D) Hash is the correct answer. It's a one-way function that converts variable-length input into a fixed-size output.

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Dyan

7 months ago

I’m a bit confused, though. Could a Feistel function also fit this description? I need to double-check my notes on that.

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Rashad

8 months ago

This question seems familiar; I practiced something similar where we discussed how hashes are used in data integrity.

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Lacey

8 months ago

I’m not entirely sure, but I feel like asymmetric and symmetric ciphers deal more with encryption rather than just returning a string.

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Mee

8 months ago

Hash functions are my strong suit. The description fits perfectly, so I'm confident option D is the correct answer.

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Cyril

8 months ago

I'm a bit confused here. Is a hash the same as a symmetric cipher? I need to review my notes on the different cryptographic primitives.

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Karima

8 months ago

Okay, I've got this. A hash function takes a variable-size input and returns a fixed-size output. That matches the description, so I'm going with option D.

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Donette

8 months ago

Agreed! Hash functions always return a fixed-size output.

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Remona

9 months ago

I think the answer is D) Hash. It fits the description perfectly.

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Vicki

9 months ago

It's definitely a Hash!

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Patrick

9 months ago

I think I remember hash functions being described as returning fixed-size outputs, so I’m leaning towards D.

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Nada

9 months ago

Ugh, I'm not sure about this one. The options seem pretty technical. I'll have to think carefully about the differences between the types of ciphers.

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Tamar

10 months ago

Hmm, this looks like a question on cryptographic functions. I think the key is to focus on the description of a fixed-size output, which points to a hash function.

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