Cryptographic hash functions are based on the mathematical concept of a checksum that cannot be reversed. As a result, they are computationally efficient and hide clues. The purpose of cryptographic hash functions is to prevent the possibility of finding two identical inputs. This feature makes cryptographic hash functions very secure.
Cryptographic hash functions are designed to prevent the ability to reverse checksums
Cryptographic hash functions are designed to prevent someone from being able to reverse a checksum, which is an essential security feature. They help secure web payments, passwords, and HTTPS protocol. SHA-256, for example, is one of the most common hash functions used in internet security. The SHA-3 algorithm is another secure hash algorithm being developed for embedded hardware.
Cryptographic hash functions work by comparing two pieces of data and creating a checksum. There is no limit on the number of checksums that can be created for a single piece of data. By making the checksums as unique as possible, even the smallest changes to the input should produce a different one.
They are not reversible
Cryptographic hash functions are one-way functions, which means that they are immutable and cannot be reversed. This is a requirement for cryptography, as encryption is not possible without authorization. A one-way function is similar to a modular function, which can give rise to the remainder of division problem.
They are computationally efficient
Cryptographic hash functions are computationally efficient, meaning they can produce a hash value in a fraction of a second. This makes them practical for applications beyond cryptography. For instance, a journalist might contact a hacker who claims to have stolen 150 million records and is holding them for ransom. However, the hacker doesn't want to show the journalist all of the records, and the journalist wants to verify the hacker's claim. The journalist would use a cryptographic hash function to check the hacker's claims.