UUID
UUID stands for Universally Unique Identifier. It's a 128-bit value (usually shown as a 36-character string) used to uniquely identify things with no centralized authority required.
Typical Format:
550e8400-e29b-41d4-a716-446655440000
Types of UUIDs (versions). The most common UUID versions are:
| Version | Based on | Notes |
|---|---|---|
| 1 | Timestamp + MAC address | Leaks time & hardware info, but sortable |
| 3 | MD5 hash of namespace+name | Deterministic |
| 4 | Random | Most common, easy, secure |
| 5 |
SHA-1 hash of namespace+name | Deterministic |