Versi UUID Dijelaskan

Setiap versi UUID — v1 hingga v8 — dengan diagram struktur, kasus penggunaan, risiko tabrakan, dan contoh kode JavaScript.

Struktur UUID

xxxxxxxx-xxxx-Mxxx-Nxxx-xxxxxxxxxxxx

time_low (32 bits)time_mid (16 bits)M = version (4 bits) + time_hi (12)N = variant (2 bits) + clock (14)node / random (48 bits)

UUID v1Time-based (MAC)Sortable

Struktur

timestamp (60-bit) + clock seq (14-bit) + MAC (48-bit)

Risiko tabrakan

Very low

6ba7b810-9dad-11d1-80b4-00c04fd430c8

Keuntungan

+Globally unique
+Sortable by time
+Embeds creation time

Kerugian

−Exposes MAC address (privacy risk)
−Requires MAC or pseudo-random node
−Clock adjustments can cause duplicates

Paling cocok untuk

Legacy systems. Avoid in new projects due to MAC address exposure.

UUID v3Name-based (MD5)Not sortable

Struktur

MD5(namespace UUID + name) → UUID

Risiko tabrakan

MD5 collision risk (low for UUIDs)

6fa459ea-ee8a-3ca4-894e-db77e160355e

Keuntungan

+Deterministic — same input = same UUID
+Can recreate UUIDs from known inputs

Kerugian

−MD5 is cryptographically weak
−Not random — attackers can predict given namespace+name
−Prefer v5 for new projects

Paling cocok untuk

Generating UUIDs from URLs, email addresses, or other stable identifiers. Use v5 instead.

UUID v4RandomNot sortable

Struktur

122 random bits + 4-bit version + 2-bit variant

Risiko tabrakan

Negligible (2^122 possibilities)

550e8400-e29b-41d4-a716-446655440000

Keuntungan

+Extremely low collision probability
+No timestamp/MAC leakage
+Simple generation — no state needed
+Most widely supported

Kerugian

−Not sortable by generation time
−Random order degrades B-tree performance in databases
−Cannot verify when a UUID was created

Paling cocok untuk

Default choice for most applications. IDs for records, sessions, tokens.

UUID v5Name-based (SHA-1)Not sortable

Struktur

SHA-1(namespace UUID + name) → UUID (top 128 bits)

Risiko tabrakan

SHA-1 — extremely low for UUID purposes

886313e1-3b8a-5372-9b90-0c9aee199e5d

Keuntungan

+Deterministic like v3, but uses SHA-1
+Stronger hash than MD5 (v3)
+Standard namespaces: DNS, URL, OID, X.500

Kerugian

−SHA-1 is fully deterministic — not suitable for secrets
−Truncates SHA-1 to 128 bits

Paling cocok untuk

Deterministic IDs from a namespace + name. Example: UUID for 'https://example.com' is always the same.

UUID v7Time-ordered RandomSortable

Struktur

Unix ms timestamp (48-bit) + version (4-bit) + random (74-bit)

Risiko tabrakan

Very low (74 random bits)

018f0b2d-4c9e-7abc-89de-f012345678ab

Keuntungan

+Sortable by time (great for database primary keys)
+Does NOT expose MAC address
+Near-zero collision probability
+RFC 9562 standard

Kerugian

−Slightly less entropy than v4 (74 vs 122 bits)
−Requires a time source
−Newer — less library support than v4

Paling cocok untuk

Database primary keys where sort order matters. Replaces v1 for time-ordered UUIDs.

UUID v8CustomSortable

Struktur

128 bits, content defined by the implementation

Risiko tabrakan

Depends on implementation

2489e9ad-f195-8b67-72da-3291d8c9fc1b

Keuntungan

+Fully customizable
+Useful for embedding application-specific data

Kerugian

−No standard semantics — interoperability must be documented
−Not widely supported

Paling cocok untuk

Experimental or vendor-specific use cases where v1–v7 don't fit.

Perbandingan Cepat

Version	Method	Sortable	Privacy-safe	Deterministic
v1	Time + MAC	✅	❌ (MAC leak)	❌
v3	MD5 hash	❌	✅	✅
v4	Random	❌	✅	❌
v5	SHA-1 hash	❌	✅	✅
v7	Time + Random	✅	✅	❌
v8	Custom	—	—	—

Menghasilkan UUID dalam Kode

// JavaScript / Node.js (built-in, Node 15+)
import { randomUUID } from 'crypto';
const v4 = randomUUID();  // → "550e8400-e29b-41d4-a716-446655440000"

// Browser
const v4 = crypto.randomUUID();

// UUID v7 (npm: uuid package v10+)
import { v7 as uuidv7 } from 'uuid';
const v7 = uuidv7();  // → "018f0b2d-4c9e-7abc-89de-f012345678ab"

// Python
import uuid
v4 = str(uuid.uuid4())  # Random
v5 = str(uuid.uuid5(uuid.NAMESPACE_URL, 'https://example.com'))

# PostgreSQL
SELECT gen_random_uuid();        -- v4 (pg 13+)
SELECT uuid_generate_v4();       -- v4 (uuid-ossp extension)
SELECT gen_random_uuid()::text;  -- as text

FAQ Versi UUID

Apa itu UUID?

UUID (Universally Unique Identifier) adalah pengidentifikasi 128-bit yang distandarisasi dalam RFC 4122. Diformat sebagai 8-4-4-4-12 karakter heksadesimal yang dipisahkan oleh tanda hubung. Dirancang unik di seluruh ruang dan waktu tanpa otoritas pusat.

Versi UUID mana yang harus saya gunakan?

Gunakan v4 untuk sebagian besar tujuan umum — dibuat secara acak dan memiliki probabilitas tabrakan yang sangat rendah. Gunakan v7 jika Anda memerlukan UUID terurut waktu untuk kunci utama database. Gunakan v5 untuk UUID deterministik dari pasangan namespace+nama.

Apa perbedaan antara UUID v4 dan v7?

UUID v4 sepenuhnya acak (122 bit acak). UUID v7 mengkodekan timestamp Unix di 48 bit pertama diikuti oleh bit acak. Ini membuat UUID v7 dapat diurutkan berdasarkan waktu pembuatan, yang secara signifikan meningkatkan kinerja indeks B-tree.

Apakah ID UUID v4 benar-benar unik?

Secara praktis ya. UUID v4 memiliki 122 bit acak, memberikan 2^122 ≈ 5,3 × 10^36 nilai yang mungkin. Untuk memiliki peluang 50% tabrakan, Anda perlu menghasilkan sekitar 2,7 × 10^18 UUID.

Version

Method

Sortable

Privacy-safe

Deterministic

Time + MAC

✅

❌ (MAC leak)

❌

MD5 hash

❌

✅

Random

❌

✅

❌

SHA-1 hash

❌

✅

Time + Random

✅

❌

Custom

—

Menghasilkan UUID dalam Kode

// JavaScript / Node.js (built-in, Node 15+)
import { randomUUID } from 'crypto';
const v4 = randomUUID();  // → "550e8400-e29b-41d4-a716-446655440000"

// Browser
const v4 = crypto.randomUUID();

// UUID v7 (npm: uuid package v10+)
import { v7 as uuidv7 } from 'uuid';
const v7 = uuidv7();  // → "018f0b2d-4c9e-7abc-89de-f012345678ab"

// Python
import uuid
v4 = str(uuid.uuid4())  # Random
v5 = str(uuid.uuid5(uuid.NAMESPACE_URL, 'https://example.com'))

# PostgreSQL
SELECT gen_random_uuid();        -- v4 (pg 13+)
SELECT uuid_generate_v4();       -- v4 (uuid-ossp extension)
SELECT gen_random_uuid()::text;  -- as text

FAQ Versi UUID

Apa itu UUID?

Versi UUID mana yang harus saya gunakan?

Apa perbedaan antara UUID v4 dan v7?

Apakah ID UUID v4 benar-benar unik?

Secara praktis ya. UUID v4 memiliki 122 bit acak, memberikan 2^122 ≈ 5,3 × 10^36 nilai yang mungkin. Untuk memiliki peluang 50% tabrakan, Anda perlu menghasilkan sekitar 2,7 × 10^18 UUID.

Versi UUID Dijelaskan

Struktur UUID

Perbandingan Cepat

Menghasilkan UUID dalam Kode

FAQ Versi UUID

References & cheat sheets

Versi UUID Dijelaskan

Struktur UUID

Perbandingan Cepat

Menghasilkan UUID dalam Kode

FAQ Versi UUID