SHA-256 Hash Generator

What is SHA-256 (Secure Hash Algorithm 256-bit)?

SHA-256 belongs to the SHA-2 family of cryptographic hash functions designed by the United States National Security Agency (NSA) and published by the National Institute of Standards and Technology (NIST) under FIPS PUB 180-4.

A cryptographic hash takes an input of arbitrary length and produces a deterministic, fixed-size 256-bit (32-byte) fingerprint, typically rendered as a 64-character hexadecimal string.

Essential Cryptographic Properties of SHA-256

• Pre-image Resistance (One-Way Function): Given a hash digest H, it is computationally infeasible to find an input message m such that SHA256(m) = H.
• Second Pre-image Resistance: Given an input message m1, it is computationally infeasible to locate another distinct message m2 that produces the identical hash.
• Collision Resistance: Finding any two distinct messages that hash to the exact same value requires an unfeasible 2^128 operations.
• The Avalanche Effect: Changing a single bit in the input message completely and unpredictably randomizes more than 50% of the output bits.

Comparison of Popular Hashing Algorithms

Computing SHA-256 in Code

Modern Browser JavaScript (Web Crypto API)

async function computeSha256(message) {
    const msgBuffer = new TextEncoder().encode(message);
    const hashBuffer = await crypto.subtle.digest('SHA-256', msgBuffer);
    const hashArray = Array.from(new Uint8Array(hashBuffer));
    return hashArray.map(b => b.toString(16).padStart(2, '0')).join('');
}

Python 3 (hashlib)

import hashlib

text = "secure_developer_password"
hash_digest = hashlib.sha256(text.encode('utf-8')).hexdigest()
print("SHA-256:", hash_digest)

Frequently Asked Questions