# Description

The **Human-to-Machine (H2M) authentication model** ensures that all access to machines, applications, or services is traceable to an authenticated human subscriber.

* The **Human Identity Authentication Service** asserts the subscriber’s identity using internal authenticators or federated external authenticators.
* The **Machine Identity Service** binds the authenticated subscriber to a registered machine, device, or service account, and issues assertions to relying parties and service providers.
* This model guarantees that every machine action can be attributed to a specific, authenticated human subscriber.