# Blockchain – All About Hash Functions and Hashing

Learn – What is a hash, what are hash functions, what is block hashing, how do hashes work, what are the benefits of hashing, and different types of hashing.

Submitted by Vaishnavi Srivastava, on January 19, 2022

## What is a Hash?

Bitcoin is nothing more than a digital record of hashes that uses proof of work and SHA-256 to provide mathematical traceability and unbreakability. A hash is a mathematical function that turns an arbitrary-length input into a fixed-length encrypted output.

As a result, its unique hash will always be the same size, regardless of the original quantity of data or file size involved. Bitcoin mining, which employs Bitcoin hashes generated using the SHA-256 function at various stages of mining, is the method through which this is ensured.

## What are Hash Functions?

A hashing function is a mathematical function that may take any type of data and any size (numbers, alphabets, media files) and produce a fixed-length output, called a hash, for that input. A hashing algorithm is a term used to describe a certain type of hashing function. There are two types of hashing algorithms (functions): One-Way Function and Two-Way Function.

## What is Block Hashing?

When discussing blockchain technology, the word hashing or (hash) is commonly used. Hashing is the process of transforming and generating any length of input data into a fixed-length string using a specific algorithm. The Bitcoin hash algorithm is SHA-256, which stands for Secure Hashing Algorithm 256 bits. Because the original data cannot be decrypted, this approach is a one-way cryptographic function.

## How do Hashes Work?

A hashing algorithm, in a nutshell, takes an endless number of bits, conducts calculations on them, and outputs a fixed number of bits. The output will always be rectified, regardless of the length of the input data. As a result, the original data is referred to as input, while the final alteration is referred to as a hash. Many hashing methods today merely differ in the way data is processed.

## What are the benefits of Hashing?

Comparing two files for equality is one of the most common uses of hashing. The generated hash values of these files will allow the owner to know if they are different without having to open two document files and compare them word-for-word.

Hashing is also used in file backup programs like SyncBack to validate the integrity of a file after it has been transferred from one location to another. A user can compare the hash values of both files to guarantee that the transmitted file is not corrupted. If they're the same, the transmitted file is a duplicate of the original.

## Different Types of Hashing

There are many various types of hash algorithms, such as **RipeMD**, **Tiger**, **xxhash**, and others, but **MD5**, **SHA-2**, and **CRC32** are the most commonly employed for file integrity checks.

**MD5**: The MD5 hashing algorithm is a one-way cryptographic function that takes any length message as input and produces a fixed-length digest value that can be used to authenticate the original message as output.**SHA-2**: The Secure Hash Algorithm 2 (SHA-2) is a series of cryptographic hash functions developed by the National Security Agency of the United States (NSA). SHA-2 is a hashing algorithm family that was developed to replace the SHA-1 method.**CRC32**: We choose the CRC32 algorithm as a hashing function because the checksums it generates are so evenly dispersed.

Comments and Discussions!