> For the complete documentation index, see [llms.txt](https://sestra.gitbook.io/sestra-whitepaper/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://sestra.gitbook.io/sestra-whitepaper/privacy-and-security/policy-and-session-model.md).

# Policy & Session Model

Policies define:

* access requirements
* session duration
* usage limits

Sessions are:

* temporary
* non-reusable
* automatically expired

Together, they provide predictable access control.