The Node.js crypto module provides an easy and efficient way to perform cryptographic operations, including creating SHA-256 hashes.

What is SHA-256?#

SHA-256 is a secure hashing algorithm that generates a fixed 256-bit (32-byte) hash value. It is commonly used for data integrity checks and cryptographic operations.

Creating a SHA-256 Hash#

To use the crypto module, you need to import it first:

const crypto = require('crypto');

// Create a hash object
const hash = crypto.createHash('sha256');

// Add data to the hash
hash.update('Hello, Rabi!');

// Finalize the hash and get the result in hex format
const result = hash.digest('hex');

console.log(result); // Outputs the SHA-256 hash

Explanation of Methods#

• crypto.createHash('sha256'): Creates a new hash object using the SHA-256 algorithm.

• update(data): Adds data to the hash object. This method can be called multiple times to add more data incrementally, especially useful for streaming large data chunks.

It processes the input data in blocks, ensuring that even large inputs can be hashed efficiently without loading everything into memory at once.

Every call to update() appends new data to the existing data within the hash object.

• digest('format'): Finalizes the hash computation and returns the result in the specified format (hex, base64, latin1, etc.). Once digest() is called, the hash object is no longer usable.