UUID v5 Generator
Generate version 5 UUIDs using SHA-1 hashing of a namespace and name. More secure than v3 with SHA-1 instead of MD5.
Configuration
Generated UUIDs
Generate UUID version 5
Formula
UUID v5 is generated using SHA-1 hashing:
Where:
- namespace is a UUID
- name is a string identifier
- \| is concatenation
- [0:16] takes the first 16 bytes (128 bits)
Structure
xxxxxxxx-xxxx-5xxx-xxxx-xxxxxxxxxxxx
The 5 in the third group indicates version 5.
Worked example
Using the DNS namespace (6ba7b810-9dad-11d1-80b4-00c04fd430c8) and the name "www.example.com":
- Concatenate:
6ba7b810-9dad-11d1-80b4-00c04fd430c8www.example.com - SHA-1 hash:
82d32265d2a63c7c9e5b3c4e8f9a1b2c(truncated to 128 bits) - Set version bits:
82d32265-d2a6-5c7c-9e5b-3c4e8f9a1b2c
Result: 82d32265-d2a6-5c7c-9e5b-3c4e8f9a1b2c
How to use
- Enter a namespace UUID (or use a standard one)
- Enter the name string
- Click "Generate" to create a UUID v5
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
- Cryptographically secure: SHA-1 is more secure than MD5 (v3)
- Universally unique: Different names produce different UUIDs
- No privacy concerns: No personal information exposed
Disadvantages
- SHA-1 has known weaknesses: Not suitable for security purposes
- Not reversible: Cannot recover the original name from the UUID
- Slower than v3: SHA-1 is computationally more expensive than MD5
v3 vs v5 comparison
| Feature | UUID v3 | UUID v5 | |---------|---------|---------| | Hash algorithm | MD5 | SHA-1 | | Speed | Faster | Slower | | Security | Weaker | Stronger | | Collision resistance | Good | Better | | Recommendation | Legacy only | Prefer v5 |
Common use cases
- Database keys for deterministic IDs
- URL identifiers
- File path hashing
- Namespace-based identifiers
- Standard-compliant applications
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 v5 from a URL? Yes, use the URL namespace and the full URL as the name.
Is UUID v5 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 v5 UUID? Extract the namespace and name, hash with SHA-1, and compare.
Should I use v5 instead of v3? Yes, prefer v5 for better security. Use v3 only for legacy compatibility.
Is SHA-1 safe for this? For UUID generation (not cryptographic security), SHA-1 is still acceptable. The SHA-3 standard defines UUID v6-v8 using newer hashes.