Hashers

What is Hashing?

Hashing is the process of taking an input (or 'message') and applying a mathematical algorithm to it in order to produce a fixed-size string of characters, known as a 'hash' or 'digest'. The key feature of a hash function is that it is a one-way operation - it is computationally infeasible to take a hash value and recreate the original input that produced it.

One of the primary uses of hashing is in password storage. When a user creates a new account and chooses a password, the password is run through a hash function before it is stored in the database. The resulting hash value is then stored instead of the original password. When the user attempts to log in by entering their password, the entered password is hashed and the resulting hash value is compared to the stored hash value. If the two values match, the user is granted access. This is more secure than storing the plaintext password, as even if an attacker gains access to the database and steals the hashed passwords, they would not be able to determine the original plaintext passwords.

Another use of hashing is for data integrity checking. When data is transmitted over a network or stored on a disk, it can be corrupted or tampered with. By running the data through a hash function and storing the resulting hash value alongside the data, it can be verified later that the data has not been tampered with. If the data is unchanged, the same input will produce the same hash value, and the integrity of the data can be verified by comparing the stored hash value with the one newly calculated. This is commonly used in file integrity checkers, digital signature and other secure communication methods.

Another use of hashing is in digital signature schemes, where a hash of a message is signed with a private key and can be verified with the corresponding public key to confirm the authenticity of the message.

Hashing is also used for searching and indexing data in large databases. By storing the hash value of an item in a database in an index, and later searching the index for that hash value instead of the item itself, it is possible to quickly locate the desired item.

Hashing is also used in cryptography, such as in key derivation functions, where a password is hashed multiple times in order to generate a cryptographically secure key to encrypt or decrypt data.

It's worth noting that, as the technology evolves, hash functions can be broken, and it's important to consider using modern, robust and unbroken hash functions like SHA-256,SHA-512..etc instead of older and broken hash function like MD5,SHA1,..etc.