SHA-256

const crypto = require('crypto');

// Hash simple
const hash = crypto.createHash('sha256')
  .update('hello world')
  .digest('hex');
console.log(hash);
// b94d27b9934d3e08a52e52d7da7dabfac484efe37a5380ee9088f7ace2efcde9

// Hash avec salt pour sécurité renforcée
const saltedHash = crypto.createHash('sha256')
  .update('password' + 'unique_salt_123')
  .digest('hex');

// HMAC-SHA256 (recommandé pour l'authentification)
const hmac = crypto.createHmac('sha256', 'secret_key')
  .update('message')
  .digest('hex');

import hashlib
import hmac

# Hash simple
message = "hello world"
hash_object = hashlib.sha256(message.encode())
hex_dig = hash_object.hexdigest()
print(hex_dig)
# b94d27b9934d3e08a52e52d7da7dabfac484efe37a5380ee9088f7ace2efcde9

# Hash de fichier (recommandé pour gros fichiers)
def hash_file(filename):
    sha256_hash = hashlib.sha256()
    with open(filename, "rb") as f:
        for byte_block in iter(lambda: f.read(4096), b""):
            sha256_hash.update(byte_block)
    return sha256_hash.hexdigest()

# HMAC-SHA256 sécurisé
key = b'secret_key'
message = b'important_data'
hmac_result = hmac.new(key, message, hashlib.sha256).hexdigest()

// Double SHA-256 (comme Bitcoin)
function doubleSHA256(data) {
  const first = crypto.createHash('sha256').update(data).digest();
  const second = crypto.createHash('sha256').update(first).digest('hex');
  return second;
}

// Proof of Work simplifié
function mineBlock(data, difficulty) {
  let nonce = 0;
  const target = '0'.repeat(difficulty);
  
  while (true) {
    const hash = doubleSHA256(data + nonce);
    if (hash.startsWith(target)) {
      return { nonce, hash };
    }
    nonce++;
  }
}