Certified In Cybersecurity CC · Free Practice Question Easy
Question 70
Which requirement is NOT necessary for a cryptographic hash function?
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A
The function must work on a variety of input sizes
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B
The function must be one way
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C
The function must be efficient to compute
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D
The function must have a low probability of producing the same output for different inputs
Reveal correct answer
Correct answer: A
Explanation
The requirement for a cryptographic hash function to work on various input sizes is not necessary. A hash function is a mathematical algorithm that takes input data and produces an output (a hash value), a compact representation of the original data. The hash function must be efficient to compute, meaning it should be able to generate the hash value quickly. It must be one-way, which means obtaining the original input data from the hash value (i.e. reversing the function) should be computationally infeasible. And it must have a low probability of producing the same output for different inputs, also known as 'collision resistance'. The input size can be fixed or variable, depending on the specific hash function, but it is not necessary for a hash function to be considered cryptographic.
Discussion
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