The standard versions are:
| Version | Binary | Meaning | |---------|--------|---------| | 1 | 0001 | Time‑based + MAC address | | 2 | 0010 | DCE Security (POSIX UID/GID) | | 3 | 0011 | Name‑based MD5 hash | | 4 | 0100 | Random (cryptographically strong) | | 5 | 0101 | Name‑based SHA‑1 hash | 7ef5bcd3-93a1-b915-5ec1-5e1ff8b3634d
7ef5bcd3‑93a1‑b915‑5ec1‑5e1ff8b3634d may look like a random jumble of hexadecimal digits, but in modern software it is often the sole identifier that ties together a user account, a transaction, a log entry, or a piece of hardware. When that string is generated correctly, it guarantees without a central authority—a property that underpins distributed systems, micro‑service architectures, and data‑privacy regulations. The standard versions are: | Version | Binary