PrepAway - Latest Free Exam Questions & Answers

What is the name of a one way transformation of a strin…

What is the name of a one way transformation of a string of characters into a usually shorter fixed-length value
or key that represents the original string? Such a transformation cannot be reversed.

PrepAway - Latest Free Exam Questions & Answers

A.
One-way hash

B.
DES

C.
Transposition

D.
Substitution

Explanation:
A cryptographic hash function is a hash function which is considered practically impossible to invert, that is, to
recreate the input data from its hash value alone. These one-way hash functions have been called “the
workhorses of modern cryptography”. The input data is often called the message, and the hash value is often
called the message digest or simply the digest.
The ideal cryptographic hash function has four main properties:
it is easy to compute the hash value for any given message
it is infeasible to generate a message from its hash
it is infeasible to modify a message without changing the hash
it is infeasible to find two different messages with the same hash.
Most cryptographic hash functions are designed to take a string of any length as input and produce a fixedlength hash value.
Incorrect Answers:
B: Data Encryption Standard (DES) is a symmetric block cipher. Data encrypted using DES can be decrypted
using the symmetric key.
C: A transposition cipher does not replace the original text with different text, but rather moves the original
values around. This encryption can be reversed and does not produce a fixed length output.
D: A substitution cipher replaces bits, characters, or blocks of characters with different bits, characters, or
blocks. This encryption can be reversed and does not produce a fixed length output.

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


Leave a Reply