A lightweight crate for retrieving the unique machine ID without needing root/admin privileges. Uses OS APIs only and does not spawn new processes!

IDs sources

• Windows: the MachineGuid value from HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Cryptography (Identifying Unique Windows Installation)
• Linux: /etc/machine-id with a fallback to /var/lib/dbus/machine-id (man page)
• macOS: IOPlatformUUID
• FreeBSD: CTL_KERN : KERN_HOSTUUID sysctl(3) with a fallback to /etc/hostid
• Other Unix: like FreeBSD, requires testing!
• Not yet implemented:
  • iOS
  • Android

Security Considerations

A machine ID uniquely identifies the host and should be treated as confidential, avoiding exposure in untrusted environments. If your application requires a stable unique identifier, avoid using the machine as it is. Instead, hash the machine ID securely with a fixed, application-specific salt.

[!WARNING]
Hashing IDs is not only a best practice today, if you store the ID somewhere (like your remote server), you actually must do it by law according to GDPR (see identifiers) and similar regulations.

[!TIP]
Virtual machines deployed from the same template often share the same machine ID. To differentiate them, include the MAC address when hashing.