Piye cara nge-hash password lan nggunakake modul crypto?

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Accepted Answer

Modul **`crypto`** built-in Node menyediakake fungsi kriptografi: hashing, enkripsi, nilai random, lan HMAC. Panganggone praktis sing paling penting — **password hashing** — duwe aturan kritis: aja nggunakake hash cepet, tujuan umum (MD5/SHA-256) kanggo password.

## Password hashing: nggunakake algoritma SLOW, salted

```js
import { scrypt, randomBytes, timingSafeEqual } from "crypto";
import { promisify } from "util";
const scryptAsync = promisify(scrypt);

// HASH a password (on signup)
async function hashPassword(password) {
  const salt = randomBytes(16).toString("hex");          // unique random salt per user
  const derived = await scryptAsync(password, salt, 64); // slow, salted derivation
  return `${salt}:${derived.toString("hex")}`;            // store salt + hash together
}

// VERIFY a password (on login)
async function verify(password, stored) {
  const [salt, hash] = stored.split(":");
  const derived = await scryptAsync(password, salt, 64);
  const hashBuf = Buffer.from(hash, "hex");
  return timingSafeEqual(hashBuf, derived); // constant-time compare (avoid timing attacks)
}
```

Poin kunci: **`scrypt`** (utawa bcrypt/argon2) intentional alon kanggo nolak brute-force; **salt unik per password** ngalahake rainbow tables; lan **`timingSafeEqual`** bandingake hash ing wektu konstan kanggo cegah timing attacks.

## Napa ora MD5/SHA-256 kanggo password

```js
// ❌ NEVER do this — SHA/MD5 are FAST, so attackers can guess billions/sec
crypto.createHash("sha256").update(password).digest("hex");
```

Hash cepet apik kanggo file checksums nanging fatal kanggo password — kecepetane persis apa sing ndadekake brute-forceable. (Ing praktik, perpustakaan kaya **bcrypt** utawa **argon2** luwih disenengi tinimbang scrypt murni kanggo ergonomi.)

## Panggunaan crypto liyane

```js
import crypto from "crypto";

crypto.randomBytes(32).toString("hex");        // secure random tokens (session ids, CSRF)
crypto.randomUUID();                            // a secure UUID v4

// HMAC — verify integrity/authenticity (e.g. webhook signatures)
crypto.createHmac("sha256", secret).update(payload).digest("hex");

// hashing for NON-secret integrity (file checksums) — SHA is fine here
crypto.createHash("sha256").update(fileBuffer).digest("hex");
```

## Napa iku penting

Nglakokake penyimpanan password kanthi bener minangka tanggung jawab keamanan kritis, lan iku kesalahan umum lan mbebayani nggunakake hash cepet utawa nglirwakake salting.

Modul `crypto` (utawa bcrypt/argon2 level luwih dhuwur) nyediakake primitif bener: slow salted hashing kanggo password, bandingane konstan-waktu, generasi random aman kanggo token, lan HMAC kanggo verifikasi integritas (kaya webhook signatures).

Pamahaman *napa* password perlu slow, salted, konstan-waktu nangani — lan yen fast hash mung kanggo checksums non-rahasia — penting kanggo mbangun authentication sing ora exposé user kanggo credential theft.