In cybersecurity, a hash function is a mathematical operation that produces a fixed-length hash or digest from a variable-length input termed the message or data. A hash function’s fundamental goal is to generate a distinctive representation of the input data, so that even minor changes to the input will yield an entirely new hash value.
These functions are frequently employed to provide data integrity and authentication. For instance, you can confirm the integrity of a file you download from the internet by comparing its hash value to the value provided by the website from which you downloaded it. You can be pretty certain that the file has not been altered with during transmission if the hash values agree.
To secure user passwords, hash functions are also utilized in password storage. The system saves the hash of a user’s password rather than saving it in plain text. The system hashes the user’s password when they log in and contrasts it with a previously stored hash. This will prevent the actual passwords from being easily obtained, even if an attacker manages to access the password database.