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UUID v3 Generator

Generate version 3 UUIDs using MD5 hashing of a namespace and name. Deterministic - same inputs always produce the same UUID.

Configuration

Generated UUIDs

Click 'Generate' to create UUIDs

Generate UUID version 3

Formula

UUID v3 is generated using MD5 hashing:

textUUID=textMD5(textnamespace∣textname)textwithversion3\\text{UUID} = \\text{MD5}(\\text{namespace} \\| \\text{name}) \\text{ with version 3}

Where:

  • namespace is a UUID (e.g., DNS namespace, URL namespace)
  • name is a string identifier
  • \| is concatenation

Structure

xxxxxxxx-xxxx-3xxx-xxxx-xxxxxxxxxxxx

The 3 in the third group indicates version 3.

Worked example

Using the DNS namespace (6ba7b810-9dad-11d1-80b4-00c04fd430c8) and the name "www.example.com":

  1. Concatenate: 6ba7b810-9dad-11d1-80b4-00c04fd430c8www.example.com
  2. MD5 hash: 82d32265d2a63c7c9e5b3c4e8f9a1b2c
  3. Set version bits: 82d32265-d2a6-3c7c-9e5b-3c4e8f9a1b2c

Result: 82d32265-d2a6-3c7c-9e5b-3c4e8f9a1b2c

How to use

  1. Enter a namespace UUID (or use a standard one)
  2. Enter the name string
  3. Click "Generate" to create a UUID v3

Standard namespaces

| Namespace | UUID | |-----------|------| | DNS | 6ba7b810-9dad-11d1-80b4-00c04fd430c8 | | URL | 6ba7b811-9dad-11d1-80b4-00c04fd430c8 | | OID | 6ba7b812-9dad-11d1-80b4-00c04fd430c8 | | X.500 | 6ba7b814-9dad-11d1-80b4-00c04fd430c8 |

Advantages

  • Deterministic: Same namespace + name always produces the same UUID
  • Universally unique: Different names produce different UUIDs
  • Privacy-safe: No personal information in the UUID itself

Disadvantages

  • MD5 is cryptographically broken: Not suitable for security purposes
  • Not reversible: Cannot recover the original name from the UUID
  • Collision risk: MD5 has known collision vulnerabilities

Common use cases

  • Database keys for deterministic IDs
  • URL identifiers
  • File path hashing
  • Namespace-based identifiers
  • Legacy system compatibility

FAQ

What is the difference between v3 and v5? v3 uses MD5, v5 uses SHA-1. v5 is preferred for security.

Can I generate a UUID v3 from a URL? Yes, use the URL namespace and the full URL as the name.

Is UUID v3 unique? Yes, globally unique as long as you use different names.

Can I use any string as namespace? Yes, but standard namespaces ensure compatibility.

How do I verify a v3 UUID? Extract the namespace and name, hash with MD5, and compare.

Should I use v3 today? Prefer v5 with SHA-1 for better security. Use v3 only for compatibility.

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