Create SHA-256 Hash of a File in Node.js

Let’s admit it, we’re living in a world where data integrity and security are more critical than ever. And if you’re like me, tinkering with Node.js, you’ve probably wondered, “How can I create a SHA-256 hash of a file?” Well, folks, you’re in the right place. Today, we’re going to dive headfirst into the exciting realm of cryptography and figure out just how to create a SHA-256 hash of a file in Node.js. So, buckle up because this is going to be a fantastic journey!

Encryption and hashing have served as the foundation for new security modules, among other network security developments. One of the most used hash algorithms is the Secure Hash Algorithm(SHA) with a digest size of 256 bits, or SHA 256. Although there are numerous variations, SHA 256 has been the most often used in practical applications. There are weaker predecessors to SHA3 like MD5, SHA1, SHA2. Interested in knowing the difference between SHA1, SHA2 & SHA3, this will give you a great insight on how SHA has evolved over the years.

SHA-256 is a part of the SHA 2 family of algorithms, where SHA stands for Secure Hash Algorithm. It was a joint effort between the NSA and NIST to introduce a successor to the weaker SHA 1 family. SHA2 was published in 2001 and has been effective ever since.

The hash function generates the same output hash for the same input string. This means that, you can use this string to validate files or text or anything when you pass it across the network or even otherwise. SHA-256 can act as a stamp or for checking if the data is valid or not.

The 256 in the name SHA-256 refers to the final hash digest value, meaning that regardless of the amount of plaintext or cleartext, the hash value will always be 256 bits.

For example –

If you want to generate SHA-256 checksum in JavaScript i.e., client side (browser), please follow this article – Create SHA-256 Hash in JavaScript

Node.js crypto module provides cryptographic functions to help you secure code and data in Node.js. It includes a set of wrappers for OpenSSL’s hash, HMAC, cipher, decipher, sign, and verify functions.

crypto is built into Node.js, so there is not configuration or custom implementation needed.

For creating SHA-256 hash in nodejs script/code, we shall use the default crypto module that comes packaged with nodejs.

If you looking to create an MD5 hash of a string, please follow the article where we discuss about this.

Creating SHA-256 Hash of a File

Now let’s learn how to create an SHA-256 hash of a file. File can be any file, a text file, a JSON file, data file etc.,

You can either require the crypto module-

const crypto = require("crypto");

or also use the modern import to import the crypto module-

import { createHash } from "crypto";

Here, let’s consider a text file for example – hello.txt having content – Welcome to Debugpointer. Let’s read the contents of the file using the fs module and read the file in a synchronous manner.

import { createHash } from "crypto";
const fs = require("fs");
const buff = fs.readFileSync("hello.txt");
const hash = createHash("sha256").update(buff).digest("hex");
console.log(hash);

The output of the above script will be an SHA-256 hash when you run the command node index.js in your shell-

b8df5aec0d11db76a655eabfc3c6d9734a4715a8de7c85e5649accaf573fe905

Prefer SHA-256 or SHA-512 or other superior cryptographic hash functions for creating a hash for passwords, integrity verification.

It’s as simple as that! You do not need any fancy npm library for creating an SHA-256 hash in Node.js.

I’m glad that you found the content useful. And that’s it, folks! Together, we’ve navigated the fascinating world of cryptography and hashed our way through Node.js. We’ve learned how to create a SHA-256 hash of a file, and trust me, it’s simpler than it initially appears. I sincerely hope you found our deep dive both educational and inspiring. As always, remember that practice makes perfect. So, go on, experiment with your files and see the magic of SHA-256 hashing in Node.js unfold before your eyes! Till next time, Happy Coding.