How to Generate Cryptographic Hashes (SHA-256, MD5, SHA-512)

A cryptographic hash function is an algorithm that takes an arbitrary amount of data input and maps it to a fixed-size bit string (a hash value).

Common Hashing Algorithms

1. SHA-256 (Secure Hash Algorithm 256-bit)

SHA-256 is part of the SHA-2 family and produces a 256-bit (32-byte) signature. It is currently the industry standard for secure password hashing and integrity checks.

2. SHA-512 (Secure Hash Algorithm 512-bit)

Similar to SHA-256 but produces a 512-bit (64-byte) value. It is faster on 64-bit hardware architectures.

3. MD5 (Message-Digest Algorithm 5)

Produces a 128-bit hash. It is mathematically broken and prone to collision attacks, meaning it should only be used for non-security checksums.

Generating Hashes in JavaScript (Web Crypto API)

Modern web browsers can generate secure SHA-256 checksums client-side using the built-in subtle crypto package:

async function digestMessage(message) {
  const msgUint8 = new TextEncoder().encode(message);
  const hashBuffer = await crypto.subtle.digest('SHA-256', msgUint8);
  const hashArray = Array.from(new Uint8Array(hashBuffer));
  const hashHex = hashArray.map(b => b.toString(16).padStart(2, '0')).join('');
  return hashHex;
}