22 January 2021

#### The Basics To Learn About Bitcoin Hash Functions

A hashing function is defined as a method that utilizes mathematical function from a string of text and generates a fixed-length value of output from any length input, hence, the output of the hashing function is called a hash. The hash is usually an alphanumeric string which is also termed as a by-product of cryptography.

**The hashing functions can be stated in to be in two types:**

**One-way function:**It is a function that generates one output of the given input however even when the output is known it is difficult to trace the input.**Two-way function:**It is a function that is right opposite to one-way function. In two way function, both the input and output is known.

A cryptographic hash function consists of various properties such as it is deterministic, its computation is faster, its pre-image resistance meaning its infeasible, a small change in the input changes the hash of the output, and every hash is unique. The thing to understand before is that every cryptocurrency has different hashing algorithms such as SHA-256, SHA-3, Scrypt, Ethash, Quark and so forth.

**In this blog we are going to discuss The Basics To Learn About Bitcoin Hash Functions:**

**Bitcoin Hash Functions**

The primary hash function of the blockchain of Bitcoin is an SHA-256 hashing algorithm which was developed in 2001 by the US NSA - National Security Agency. The hash function is utilized for the factors such as of its unique hash value, the computation of the hashing speed is faster and the hash function is secured. In bitcoin, it is used to add a new block in the blockchain through the process of mining consisting of bitcoin block hashing algorithm.

So with SHA-256, the input can be of any given length but the output is going to be a 256-bits length. For instance, the input could be any bitcoin transaction that would run through the process of its hashing algorithm, which here is SHA-256 and would generate a fixed-length of output.

**Also Read,** *What is Bitcoin mining?*

Hence, bitcoin is based on blockchain technology through the ledger system it uses PoW - Proof Of Work consensus and SHA-256 to facilitate the unique property it holds. Thus, bitcoin mining is the process that provides surety and uses the SHA-256 functions to generate Bitcoin hashes.

During the mining process, the miners need to ensure that while hashing the block header it leads to an equal or lesser hash then the target hash in order to add the block in the blockchain. A block header consists of - the block version number, the timestamp, current difficulty target, hash of the previous block, hash of the Merkle root and nonce. The target changes after every 2016 blocks and it should consist of an alphanumeric number of 18 or more zeros considering the target, also the miner needs to play the nonce to get its hash accepted, hence, the accepted target is then called as a Bitcoin Hash.

The entire process mentioned above requires a great amount of computational power, well-equipped hardware, it is a costly process and the miner has to be work faster to achieve the outcome and finally receive its reward!

An example of such Bitcoin Hash is- 0000000000000000001057c33ca0814be1c1a6dd7337dbc06b4d83331796f07d