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Invariant-Closed System Design (ICSD)
draft-dpa-icsd-01

Document Type Active Internet-Draft (individual)
Author Benjamin Anthony Fisher
Last updated 2026-03-16
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draft-dpa-icsd-01
Network Working Group                                        B.A. Fisher
Internet-Draft                                                   DPA R&D
Intended status: Informational                             16 March 2026
Expires: 17 September 2026

                 Invariant-Closed System Design (ICSD)
                           draft-dpa-icsd-01

Abstract

   Invariant-Closed System Design (ICSD) defines an architectural
   principle for building systems in which all representable states are
   valid and compliant by construction.  Rather than relying on runtime
   detection, validation, or remediation of invalid or abusive
   behaviour, ICSD ensures that invalid states are structurally
   unrepresentable through constrained state models, invariant-bound
   transitions, and authority-anchored truth sources.

   This document introduces the ICSD concept, its core properties,
   design trade-offs, and applicability to compliance-critical domains
   such as payroll, taxation, financial reporting, and regulated
   infrastructure.  It defines the current architectural and semantic
   baseline for the ICSD portion of the suite.

   This document is part of an experimental, research-oriented
   Independent Stream suite.  It defines the current normative baseline
   for trust objects, validation rules, and security semantics within
   its scope.  Hard interoperability is expected for shared object
   semantics and validation rules.  Full wire-level, clustering, and
   proof-family interoperability is not claimed everywhere yet; the
   remaining details are intentionally profile-defined or deferred where
   companion work has not yet closed them.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at https://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

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   This Internet-Draft will expire on 17 September 2026.

Copyright Notice

   Copyright (c) 2026 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents (https://trustee.ietf.org/
   license-info) in effect on the date of publication of this document.
   Please review these documents carefully, as they describe your rights
   and restrictions with respect to this document.

Table of Contents

   1.  Scope and Status  . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Executive Summary . . . . . . . . . . . . . . . . . . . . . .   3
   3.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   4
   4.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   5
   5.  Core Principle  . . . . . . . . . . . . . . . . . . . . . . .   6
   6.  Invariant-Bound State Space . . . . . . . . . . . . . . . . .   6
   7.  Survivability and Sovereignty Invariants  . . . . . . . . . .   7
     7.1.  Survivability Invariant . . . . . . . . . . . . . . . . .   7
     7.2.  No Singular Trust Anchor Invariant  . . . . . . . . . . .   7
     7.3.  Bootstrap Trust Boundary  . . . . . . . . . . . . . . . .   8
     7.4.  Fork Survivability  . . . . . . . . . . . . . . . . . . .   8
     7.5.  Closure Is Not Centralisation . . . . . . . . . . . . . .   9
     7.6.  Transparent Accountability Invariant  . . . . . . . . . .   9
     7.7.  Anti-Kill-Switch Principle  . . . . . . . . . . . . . . .   9
   8.  Authority-Anchored Truth  . . . . . . . . . . . . . . . . . .   9
   9.  Non-Representable Invalid States  . . . . . . . . . . . . . .  10
   10. Elimination of Reactive Enforcement . . . . . . . . . . . . .  10
   11. Auditability and Compliance . . . . . . . . . . . . . . . . .  11
   12. Design Trade-offs . . . . . . . . . . . . . . . . . . . . . .  12
   13. Comparison with Traditional Designs . . . . . . . . . . . . .  12
   14. Applicability . . . . . . . . . . . . . . . . . . . . . . . .  13
     14.1.  Applicability to Identity-Bound Security Systems . . . .  13
   15. Security Considerations . . . . . . . . . . . . . . . . . . .  13
   16. Conclusion  . . . . . . . . . . . . . . . . . . . . . . . . .  14
   17. One-Sentence Summary  . . . . . . . . . . . . . . . . . . . .  14
   18. IANA Considerations . . . . . . . . . . . . . . . . . . . . .  14
   19. Normative References  . . . . . . . . . . . . . . . . . . . .  14
   20. Informative References  . . . . . . . . . . . . . . . . . . .  15
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .  15

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1.  Scope and Status

   This Internet-Draft is part of an experimental, research-oriented
   suite prepared for the Independent Stream.  It is published to enable
   structured technical review, experimentation, and architectural
   discussion around Invariant-Closed System Design (ICSD).

   Within that suite, this document defines the current normative
   baseline for trust objects, validation rules, and security semantics
   relevant to invariant-bound state transitions, evidence handling, and
   authority-anchored truth evaluation.  Hard interoperability is
   expected for shared object semantics and validation rules.

   The material is a research artefact.  It does not claim technical
   completeness, production readiness, or endorsement by the IETF or any
   other standards body, and it is not presented as a standards-track
   specification.

   Full wire-level, clustering, and proof-family interoperability is not
   claimed everywhere yet; relevant suite-level details remain
   intentionally profile-defined or deferred.  ICSD is therefore
   presented primarily as an architectural and semantic baseline rather
   than a complete protocol, and it does not mandate a particular
   programming language, database technology, exchange format, or
   deployment model.

   A reference Python implementation and tooling baseline for ICSD is
   available as dpa-icsd on PyPI.  As of March 6, 2026, the latest
   listed release is 1.0.10 and includes the icsd-dpa CLI for evidence
   verification and linting.  This implementation is informative only
   and does not define the normative specification.

2.  Executive Summary

   Many systems attempt to achieve correctness and compliance by
   accepting broad inputs, then using validation, monitoring,
   moderation, and repair mechanisms to detect and handle invalid
   behaviour after it occurs.  This reactive approach increases
   operational complexity, creates ambiguous intermediate states, and
   expands the attack and abuse surface.

   Invariant-Closed System Design (ICSD) proposes a different approach:
   design the system such that only valid states can exist.  In an ICSD
   system, invalid and non-compliant states are not "handled" at runtime
   because they are not representable in the system's state space.

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   ICSD shifts complexity from runtime policing towards upfront
   modelling.  It improves auditability by ensuring every persisted
   state is valid, and it reduces abuse opportunities that rely on
   malformed, partial, or inconsistent internal state.

3.  Terminology

   *Requirements Language:* The key words "MUST", "MUST NOT",
   "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT",
   "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in [RFC2119] and
   [RFC8174] when, and only when, they appear in all capitals.

   *System State:* The complete set of values that determines system
   behaviour at a given instant, including persisted data and any in-
   scope in-memory state.

   *Representable State:* A state that the system can encode in its data
   model and reach through its defined transitions.

   *Invariant:* A condition that MUST hold for all representable states
   of the system (e.g., legal constraints, accounting identities,
   authorisation constraints, or schema requirements).

   *Invariant-Closed:* A property of a system where the set of
   representable states is closed under the invariants; i.e., every
   representable state satisfies every invariant.

   *Authority-Anchored Truth Source:* An external or internal source of
   truth that is treated as authoritative for specific facts (e.g.,
   statutory registries, regulated rulesets, signed identity assertions,
   or versioned policy artefacts).

   *Bootstrap Trust Boundary:* The admission boundary between a
   principal that is not yet inside the closed trust domain and one that
   has completed explicit bootstrap validation under accepted seed
   material, policy, and authority constraints.

   *No Singular Trust Anchor:* A design property in which no single
   issuer, registry, revocation service, controller, or bootstrap source
   can unilaterally determine continued legitimacy for the whole system.

   *Recovery / Re-Enrolment:* A privileged trust transition by which a
   previously known principal returns to an admissible state under
   tighter artefact, supersession, and policy checks than ordinary
   steady-state operation.

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   *Fork Survivability:* A property of an invariant-closed system in
   which independent continuation remains locally verifiable even if
   previously aligned authorities, registries, or operators diverge.

   *Reactive Enforcement:* Any mechanism that detects, mitigates, or
   remediates invalid behaviour after it has been encoded as a system
   state (e.g., validation errors on persistence, moderation queues,
   anomaly scoring, or repair jobs).

4.  Introduction

   Contemporary systems often permit a broad range of inputs and states,
   depending on reactive mechanisms - validation checks, monitoring,
   moderation, or repair - to handle invalid, non-compliant, or abusive
   behaviour after it occurs.  This reactive approach increases
   operational complexity, maintenance burden, and exposure to errors or
   attacks that exploit inconsistent or intermediate states.

   Invariant-Closed System Design (ICSD) offers an alternative paradigm:
   systems are structured so that only valid states can exist.  Invalid
   or non-compliant states are not detected and corrected - they are
   prevented by design, as they have no representation in the system's
   state space.

   The core axiom of ICSD is: If a system state can exist, it is already
   valid.  Correctness, regulatory compliance, and legitimacy are
   embedded directly into the type system, input constraints, transition
   rules, and data sources.

   This document outlines the ICSD principle, contrasts it with
   traditional reactive designs, and explores its benefits in domains
   where trust assumptions are minimal and authoritative sources define
   ground truth.  Examples draw from production experience in payroll
   and taxation systems, where invariants are non-negotiable.

   ICSD is particularly relevant to high-assurance environments,
   including financial systems, identity management, regulatory
   reporting, and secure infrastructure protocols.

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   This draft should therefore be read as part of an experimental,
   research-oriented Independent Stream suite and as the current
   normative baseline for trust objects, validation rules, and security
   semantics within its scope.  Hard interoperability is expected for
   shared object semantics and validation rules.  Full wire-level,
   clustering, and proof-family interoperability is not claimed
   everywhere yet; relevant details remain intentionally profile-defined
   or deferred in companion work.  Multiple authorities or truth sources
   do not by themselves solve decentralisation, and broader availability
   properties still depend on explicit profile and deployment choices.

5.  Core Principle

   The foundational axiom of ICSD is: *If a system state can exist, it
   is already valid.*

   Reactive design (detect+repair) | ICSD design (invalid unrep.)

      input                        | input (constrained)
        |                          |     |
        v                          |     v
    [broad parsing]                | [invariant-safe encoding]
        |                          |     |
        v                          |     v
    [state may be invalid]         | [state always valid]
        |                          |     |
        v                          |     v
    [detect/moderate/repair]       | [audit transition history]

       Figure 1: Reactive enforcement versus invariant-closed design

   In a reactive design, the system must cope with invalid-but-encoded
   states and expend effort detecting, triaging, and correcting them.
   In an invariant-closed design, invalid states are unreachable: the
   system's representational model does not permit them, and transitions
   preserve invariants by construction.

   ICSD does not imply that a system is small or trivial.  Rather, it
   implies that as complexity increases, the modelling discipline
   increases as well: each additional state and transition is admitted
   only if it can be expressed in a way that preserves invariants.

6.  Invariant-Bound State Space

   An ICSD system defines a closed set of invariants: conditions that
   must always hold true.  These invariants define the system's state
   space.  The system MUST ensure that:

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   *  all representable states satisfy all invariants;

   *  all state transitions preserve invariant validity; and

   *  no mechanism exists to bypass or temporarily suspend invariants.

   In practice, this typically requires modelling state as a finite set
   of well-defined types (or records) whose construction is only
   possible through invariant-preserving transitions.

   Examples of non-negotiable invariants in compliance-critical domains
   include:

   *  a payroll run cannot exist without a verified legal entity and an
      applicable tax context;

   *  a regulatory submission artefact cannot exist unless schema and
      policy validation have passed; and

   *  an authorisation grant cannot exist without a verified identity
      and an explicit scope of authority.

   In ICSD, invariants are not optional checks; they define what the
   system can represent.

7.  Survivability and Sovereignty Invariants

   This section defines constitutional invariants for ICSD systems that
   operate in adversarial, decentralised, or jurisdictionally fragmented
   environments.

7.1.  Survivability Invariant

   An invariant-closed system MUST remain operational if any single
   administrative, organisational, or jurisdictional entity ceases
   operation or becomes adversarial.

   Consequently, an invariant-closed system MUST NOT require any single
   dependency class as an operational precondition, including any single
   identity issuer, certificate authority, revocation service, relay
   operator, directory service, or bootstrap source.

7.2.  No Singular Trust Anchor Invariant

   No invariant-closed system SHALL depend on a singular trust anchor
   whose compromise invalidates the system's operational guarantees.

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   This prohibition includes, but is not limited to, central CAs, global
   revocation lists, authorising bodies, mandatory bootstrap registries,
   mandatory relay controllers, or singular revocation services when
   used as unique trust anchors.

7.3.  Bootstrap Trust Boundary

   An invariant-closed system is not self-originating.  A brand-new
   device, node, or principal is not yet within the closed trust domain
   and must first be admitted through an explicit bootstrap process.
   Bootstrap trust is therefore a first-class architectural concern
   rather than an implicit property of the steady-state protocol.

   Deployments must define which bootstrap sources they accept.
   Acceptable bootstrap inputs may include manufacturer attestation,
   owner-installed or operator-installed seed trust, pre-provisioned
   deployment credentials, local attestation ceremony, physically
   mediated enrolment, custodial onboarding authority, verified HIL-
   assisted enrolment, or administrative or MDM-style approval under
   signed policy.  The bootstrap authority MUST be explicit, narrow,
   auditable, and non-magical.

   Bootstrap trust does not, by itself, confer unlimited steady-state
   authority.  Once bootstrap is complete, ordinary invariants, scope
   limits, revocation rules, and policy validation MUST apply, and the
   bootstrap path MUST NOT silently bypass them.

   Bootstrap, recovery, and re-enrolment are privileged trust
   transitions and are especially suitable for invariant-closed
   modelling because admissible artefacts, bounded authority,
   supersession rules, and fail-closed outcomes can be made explicit.
   An ICSD-aligned system should make unauthorised or ambiguous Day Zero
   and recovery states structurally unrepresentable rather than merely
   detectable after admission.

7.4.  Fork Survivability

   An invariant-closed system MUST permit independent continuation
   (fork) without invalidating identity or operational semantics for
   participating nodes.

   Post-fork operation MUST remain locally verifiable and MUST NOT
   depend on continued alignment to a canonical registry for legitimacy.

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   For identity-bound systems, this implies that identities remain
   usable post-fork, mediator operation remains registry-independent,
   trust relationships remain independently maintainable, and
   accountability or transparency artefacts remain locally interpretable
   even when no single post-fork authority is universally recognised.

7.5.  Closure Is Not Centralisation

   Closed does not mean centrally controlled.

   Closure refers to integrity-bound operational constraints and
   cryptographically sealed state-transition semantics, not
   administrative centralisation.

7.6.  Transparent Accountability Invariant

   Invariant-closed systems SHOULD provide cryptographic transparency or
   accountability mechanisms sufficient to permit independent
   verification of system behaviour and state transitions.

   Examples include signed append-only transparency logs, cryptographic
   reachability evidence, and verifiable misbehaviour proofs.

7.7.  Anti-Kill-Switch Principle

   No invariant-closed system SHALL include unilateral global revocation
   or termination capabilities absent multi-party cryptographic
   consensus.

8.  Authority-Anchored Truth

   Where possible, ICSD systems anchor truth to authoritative sources
   rather than user assertion.  This reduces trust assumptions and
   limits the risk of fabricated, inconsistent, or self-contradictory
   state.

   Authority anchoring does not require a singular administrative
   authority.  Multiple independent authoritative sources MAY coexist if
   they preserve the invariants defined by the system.

   Authority anchoring commonly appears as:

   *  company identity derived from statutory registries;

   *  tax calculations constrained by authoritative rulesets and
      versioned guidance;

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   *  roles and authority derived from official records or
      cryptographically signed policy artefacts; and

   *  identity claims derived from verified credentials rather than
      mutable profile fields.

   User input is treated primarily as selection, initiation, or proposal
   - not as the authoritative ground truth.  Where user input is
   necessary (e.g., choosing a tax code), the representational model
   SHOULD restrict it to a set of invariant-safe options.

9.  Non-Representable Invalid States

   A defining property of ICSD is the elimination of representable
   invalid states.  In an ICSD system, there are no:

   *  invalid-but-saved records;

   *  broken intermediate states;

   *  speculative or partially complete entities; or

   *  privileged objects created before authority has been verified.

   If a configuration or object cannot be valid, it has no
   representation in storage or memory.  This removes entire classes of
   bugs and abuse vectors associated with partial, inconsistent, or
   order-dependent state.

10.  Elimination of Reactive Enforcement

   Because invalid behaviour cannot be encoded, ICSD systems minimise or
   eliminate the need for reactive enforcement mechanisms such as:

   *  heuristic abuse detection and anomaly scoring;

   *  moderation queues and manual review pipelines;

   *  background repair jobs for data quality;

   *  error-driven state reconciliation; and

   *  ad hoc "fix-forward" scripts to correct invalid persistence.

   Reactive enforcement is replaced by structural impossibility.  The
   system does not monitor for invalid behaviour; it cannot represent
   it.

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   This does not remove all monitoring needs.  Systems may still monitor
   for availability, performance, and suspicious but valid activities.
   ICSD specifically targets the class of failures where invalidity
   arises from representable internal state.

11.  Auditability and Compliance

   In ICSD systems, auditability emerges as a side effect of correct
   design:

   *  every persisted state is valid;

   *  audit logs describe state transitions, not error recovery;

   *  compliance evidence is implicit in system history; and

   *  reconciliation becomes verification rather than investigation.

   A practical consequence is that auditors and operators can reason
   over the system using a smaller set of cases: "what valid state did
   we enter, when, and under what authority?" rather than "what went
   wrong and how did we patch it?"

   ICSD is especially valuable where invariants are externally imposed
   (e.g., law and regulation) and where failure modes have significant
   cost (e.g., financial penalties, reputational harm, or operational
   shutdown).

   High-value control-plane elements are especially strong candidates
   for invariant-closed modelling.  Examples include RN controllers,
   patch or release manifests, grant ledgers, route-policy objects, and
   similar authority-bearing artefacts in identity-centric systems.  For
   such objects, the design goal is that unsigned overrides, invalid
   signer sets, rollback states, policy-ineligible transitions, and
   partial-write artefacts are not merely detected after the fact but
   are structurally unrepresentable.

   As a small informative example, a UZPIF-compatible deployment could
   model RN controller state acceptance as an invariant-closed
   transition: a controller update would become admissible only when the
   signed controller object, the authority set accepted at the bootstrap
   trust boundary or by later recovery / re-enrolment, epoch or sequence
   precedence, and applicable policy scope all validate together.  This
   illustrates a compatible design discipline, not a requirement that
   UZPIF implementations adopt ICSD as a mandatory framework,
   prerequisite layer, or protocol dependency.

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12.  Design Trade-offs

   ICSD deliberately shifts complexity away from runtime policing and
   remediation towards upfront modelling and invariant definition.  This
   increases initial design discipline but can reduce long-term
   maintenance cost, operational overhead, abuse surface area, and
   regulatory exposure.

   Common trade-offs include:

   *  *Reduced flexibility:* inputs and workflows may be more
      constrained than in permissive systems.

   *  *Upfront modelling cost:* invariants must be identified,
      formalised, and tested early.

   *  *Migration complexity:* legacy datasets containing invalid state
      may require transformation.

   *  *Profile management:* different jurisdictions or policy regimes
      may require explicit profiles.

   ICSD is not a statement that "validation is bad".  It is a statement
   about where validation belongs: as part of constructing representable
   state, rather than as a recurring operational burden after invalidity
   has already been encoded.

13.  Comparison with Traditional Designs

    +===========================+====================================+
    | Traditional design        | ICSD design                        |
    +===========================+====================================+
    | Accepts broad input       | Accepts only invariant-safe input  |
    +---------------------------+------------------------------------+
    | Detects invalid behaviour | Cannot represent invalid behaviour |
    +---------------------------+------------------------------------+
    | Repairs bad states        | Prevents bad states                |
    +---------------------------+------------------------------------+
    | Relies on monitoring      | Relies on structure and modelling  |
    +---------------------------+------------------------------------+
    | Compliance as process     | Compliance as property             |
    +---------------------------+------------------------------------+
    | Security controls often   | Many controls become inherent to   |
    | layered on top            | the state model                    |
    +---------------------------+------------------------------------+

              Table 1: Traditional design compared with ICSD

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   ICSD does not remove the need for good engineering practices such as
   testing, change control, or operational security.  It changes the
   baseline: correctness and compliance become properties of what the
   system can represent.

14.  Applicability

   ICSD is particularly well suited to domains where:

   *  correctness is mandatory and errors have high cost;

   *  authoritative sources define ground truth;

   *  trust cannot be assumed; and

   *  regulatory exposure is high.

   Example domains include payroll and taxation, financial systems,
   identity and access control, regulatory reporting, and secure
   infrastructure and protocol design.

14.1.  Applicability to Identity-Bound Security Systems

   In identity-first architectures, a common failure mode is the
   existence of "privileged but invalid" objects, such as a grant that
   exists before identity is verified, or a session that exists before
   policy checks are applied.  ICSD mitigates this by making such
   objects unrepresentable: the only representable grants and sessions
   are those that are already bound to verified identity and explicit
   authority.

   This principle complements identity-bound frameworks and transports
   such as [UZPIF], [UZP], and [TLS-DPA], where correctness and
   authorisation are expected to be intrinsic properties of the
   connection and its negotiated state.  ICSD is therefore best read as
   a design discipline and implementation approach that fits such
   systems well, not as a suite-mandatory governance layer, required
   subsystem, or deployment prerequisite.

15.  Security Considerations

   ICSD can reduce attack surface by eliminating representable invalid
   states.  Many classes of injection, abuse, and privilege escalation
   rely on malformed, partial, or inconsistent internal state; ICSD
   systems make such states unreachable by design.

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   However, ICSD is not a complete security model.  A representable
   state being "valid" with respect to invariants does not guarantee
   that it is desirable.  Attackers can still:

   *  perform harmful actions that are valid within policy (e.g.,
      authorised but abusive use);

   *  target the integrity of truth sources (e.g., poisoning authority
      data);

   *  exploit incorrect invariant definitions (i.e., specification
      bugs); and

   *  attack availability (e.g., denial-of-service) regardless of state
      validity.

   Designers should treat invariants and authority sources as security-
   critical artefacts: they SHOULD be versioned, reviewed, tested, and
   auditable.  Where possible, authority inputs SHOULD be authenticated
   (e.g., signatures, provenance records) and changes SHOULD be subject
   to explicit change control.

16.  Conclusion

   Invariant-Closed System Design reframes correctness from a runtime
   concern into a structural property.  By designing systems where
   invalid behaviour is not prevented but structurally impossible, ICSD
   can reduce operational complexity, improve auditability, and
   strengthen trustworthiness in compliance-critical environments.

   ICSD is best viewed as a discipline: it rewards rigorous modelling
   and clear definitions of invariants and authority.  Where those
   conditions hold, it can remove entire classes of failures that
   otherwise demand continuous monitoring and remediation.  It can
   inform architectures such as UZPIF, UZP, and TLS-DPA without being a
   prerequisite for deploying or understanding them.

17.  One-Sentence Summary

   Invariant-Closed System Design is the practice of building systems
   where invalid behaviour is not prevented - it is structurally
   impossible.

18.  IANA Considerations

   This document has no IANA actions.

19.  Normative References

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   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <https://www.rfc-editor.org/info/rfc2119>.

   [RFC8174]  Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
              2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
              May 2017, <https://www.rfc-editor.org/info/rfc8174>.

20.  Informative References

   [TLS-DPA]  Fisher, B. A., "TLS-DPA: An Identity-Bound Security
              Protocol for Traditional, Overlay, and Zero-Port
              Transports", Work in Progress, Internet-Draft, draft-dpa-
              tls-dpa,
              <https://datatracker.ietf.org/doc/html/draft-dpa-tls-dpa>.

   [UZP]      Fisher, B. A., "UZP: Universal Zero-Port Transport
              Protocol", Work in Progress, Internet-Draft, draft-dpa-
              uzp-transport, <https://datatracker.ietf.org/doc/html/
              draft-dpa-uzp-transport>.

   [UZPIF]    Fisher, B. A., "The Universal Zero-Port Interconnect
              Framework (UZPIF): An Identity-Centric Architecture for
              Post-Port Networking", Work in Progress, Internet-Draft,
              draft-dpa-uzpif-framework,
              <https://datatracker.ietf.org/doc/html/draft-dpa-uzpif-
              framework>.

Author's Address

   Benjamin Anthony Fisher
   DPA R&D Ltd (https://www.dpa-cloud.co.uk)
   Email: b.fisher@dpa-cloud.co.uk
   URI:   https://orcid.org/0009-0004-4412-2269

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