---
title: "State machines"
description: ""
url: https://nexusobservatory.com/spec/states/
publisher: Nexus Observatory Inc.
updated: 2026-11-04
---

[Observatory Protocol](https://nexusobservatory.com/)

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[Specification](https://nexusobservatory.com/spec/)

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**State machines** 

# States are entered on evidence, never on assertion.

Eleven state machines, from enrolment to revocation. Every transition is typed, and a state is entered only on the evidence its transition names.

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**Functions**: 12
**State machines**: 11
**Objects**: 21
**Standards**: 48

## The practice this part continues.

**Time A shared clock**: Coordinated Universal Time is computed by the BIPM from data contributed by timing laboratories; IEEE 1588 defines the Precision Time Protocol, and ITU-T G.8275.1 profiles it for phase and time synchronisation across networks. In the protocol, time is a function in its own right: a measurement whose clock cannot be trusted cannot be published as trusted. \[1\]\[2\]\[3\]
**2023 Attested identity**: The IETF RATS architecture (RFC 9334) describes how one party appraises evidence about the state of another. The protocol’s Join and Admit functions apply that model to instruments: a participant begins untrusted and is admitted on evidence, not on assertion. \[4\]

## Typed transitions, evidence at every step.

Select a machine, then a state, to read what it leads to and the evidence each transition requires.

UNENROLLED

DISCOVERED

ATTESTING

IDENTITY\_ISSUED

POLICY\_BOUND

PLAN\_STAGED

LOCAL\_READY

DEGRADED

QUARANTINED

REVOKED

**Selected state**: UNENROLLED
**Leads to**: DISCOVERED when hardware inventory recorded QUARANTINED when bootstrap integrity failure
**Reached from**: Entry state

## References

Sources for the historical and standards statements on this page.

1. Bureau International des Poids et Mesures. "Realizing and disseminating international reference time scales: UTC, UTCr and TT(BIPM)." [www.bipm.org/en/time-ftp](https://www.bipm.org/en/time-ftp)
2. IEEE Std 1588-2019. "IEEE Standard for a Precision Clock Synchronization Protocol for Networked Measurement and Control Systems." [doi.org/10.1109/IEEESTD.2020.9120376](https://doi.org/10.1109/IEEESTD.2020.9120376)
3. ITU-T Recommendation G.8275.1. "Precision time protocol telecom profile for phase/time synchronization with full timing support from the network." [www.itu.int/rec/T-REC-G.8275.1](https://www.itu.int/rec/T-REC-G.8275.1)
4. Birkholz, H., et al. (2023). RFC 9334, "Remote ATtestation procedureS (RATS) Architecture." IETF. [www.rfc-editor.org/rfc/rfc9334](https://www.rfc-editor.org/rfc/rfc9334)
5. Bradner, S. (1997). RFC 2119, "Key words for use in RFCs to Indicate Requirement Levels." IETF. [www.rfc-editor.org/rfc/rfc2119](https://www.rfc-editor.org/rfc/rfc2119)
6. Leiba, B. (2017). RFC 8174, "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words." IETF. [www.rfc-editor.org/rfc/rfc8174](https://www.rfc-editor.org/rfc/rfc8174)

## Read it, test it, propose a change.

The Observatory Protocol is an open specification. Any party may implement it, and every change is proposed and decided in public.

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