What is an HWID, and how is it used in software licensing?

HWID in one paragraph

A hardware ID is a stable identifier for a single machine. When software is activated, it sends the HWID along with the license key; the licensing server remembers it, and from then on accepts that key only from the same machine. If the key is copied to another computer, the HWID will not match and the key is refused.

Where the ID comes from

Every major operating system already keeps a per-installation machine identifier. The Foliox SDKs read these:

Why the ID is hashed

The raw identifier never needs to leave the computer. The SDK sends a SHA-256 hash of it instead: the server can still recognise the same machine next time, but cannot work back to the original value. Full details are in the device ID specification.

HWID lock vs HWID ban

An HWID lock ties one license key to one machine. An HWID ban blocks a machine from using any key — for example after a key was leaked or abused. Foliox License has both: every key can be device-locked, and the operator’s blocklist refuses a device hash or an IP address across the whole license API.

What changes an HWID

Reinstalling an operating system on the same hardware usually keeps the ID on Windows and macOS, but not always on Linux. Cloned virtual machines and containers without a persisted machine ID can share or change IDs. When a customer’s ID really changes, they request a device reset on the license check page and you approve it (device resets are included from the Starter plan up).

Honest limits

Someone with full control of a computer can spoof an identifier, and no client-side check can stop that completely. HWID locking is about making casual sharing and key resale pointless, not about making cracking impossible — the security model spells out what it can and cannot do.