SHA256 Algorithm Explained

Arthur Raphel
2 min readMar 15, 2021


Here we will dwell into the most popular cryptocurrency hashing algorithm — SHA256

If you are a cryptocurrency aficionado, then you might have heard about hashing and cryptocurrency hashing algorithms. Hashing algorithms are used to make blockchains of cryptocurrencies protected. They are the building blocks of cryptos. The Bitcoin blockchain employs the SHA256 hash algorithm. We will have a comprehensive look into SHA256 algorithms. For that, we also want to know what actually hashing is, what it does in blockchain, and about secure hash algorithms.

What is Hashing?

A hash function is a cryptographic function that uses data of any length and returns a fixed-length output. This method of using a given hash function to process input is called hashing. The final output of that hash function is called a hash.

SHA-2 (Secure Hash Algorithm 2), of which SHA256 is a part, is one of the most common hashing algorithms out there. In this write-up, we are going to break down every step of the algorithm as easy as we can and work through a real-life example by hand.

SHA256 is one of the heir hash functions to SHA-1 (collectively referred to as SHA-2) and is one of the most effective hash functions available. SHA256 is not much more complicated to code than SHA1 and has not yet been settled in any way. The 256-bit key delivers a good partner-function for AES. It is described in the NIST (National Institute of Standards and Technology) standard ‘FIPS 180–4’. National Institute of Standards and Technology also provide several test vectors to check the correctness of the implementation.

In this JavaScript implementation, we have examined to make the script as precise and concise as possible, and equitably as close as practicable to the NIST specification, to make the execution of the script readily recognisable.

Read more on : SHA256 Algorithm Explained!- A Must Read

This script is orientated toward hashing text messages somewhat than binary data. The standard grants hashing byte-stream (or bit-stream) messages only. The text which contains (multi-byte) characters outside ISO 8859–1 (i.e. accented characters outside Latin-1 or non-European character sets — anything with Unicode code-point above U+FF), can’t be encoded 4-per-word, so the script defaults to encoding the text as UTF-8 before hashing it.

What Is a Hash Function?

Three of the principal purposes of a hash function are:

  • To scramble data deterministically
  • To accept input of any length and output a fixed-length result

SHA-2 vs SHA-256

SHA-2 is a cryptocurrency algorithm, a generalized idea of how to hash data. SHA-256 sets new constants that define the SHA-2 algorithm’s behaviour. One such constant is the output size. “256” and “512” refer to their corresponding output digest sizes in bits.



Arthur Raphel

A professional with over 26 years of experience working within the advertising and marketing communications industry.