Internet Engineering Task Force J. van de Meent Internet-Draft Humotica Intended status: Informational 9 May 2026 Expires: 10 November 2026 TIBET Causal Time Substrate draft-vandemeent-tibet-causal-time-00 Abstract This document describes the TIBET Causal Time Substrate, a forward- only causal ordering model for identity-bound distributed systems. TIBET does not treat wall-clock time as the primary ordering primitive. Instead, it uses a cryptographically bound logical-time structure encoded through append-only linkage, monotonic generation counters, and signed causal references. External wall-clock sources, including NTP, RFC 3161 timestamping services, Roughtime, GNSS, or public ledger timestamps, are treated as auxiliary alignment anchors rather than as the constitutive source of event order. The core claim is simple: TIBET is a forward-only causal substrate that enables recovery and reversibility without rewriting history. 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." This Internet-Draft will expire on 10 November 2026. Copyright Notice Copyright (c) 2026 IETF Trust and the persons identified as the document authors. All rights reserved. van de Meent Expires 10 November 2026 [Page 1] Internet-Draft TIBET Causal Time May 2026 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. Code Components extracted from this document must include Revised BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Revised BSD License. Table of Contents 1. Status of This Memo . . . . . . . . . . . . . . . . . . . . . 2 2. Problem Statement . . . . . . . . . . . . . . . . . . . . . . 3 3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 4. Design Goals . . . . . . . . . . . . . . . . . . . . . . . . 4 5. Model Overview . . . . . . . . . . . . . . . . . . . . . . . 4 6. Relation to Lamport and Related Work . . . . . . . . . . . . 4 7. Forward-Only Property . . . . . . . . . . . . . . . . . . . . 4 8. Event Classes . . . . . . . . . . . . . . . . . . . . . . . . 4 9. External Time Anchors . . . . . . . . . . . . . . . . . . . . 5 10. Drift and Alignment . . . . . . . . . . . . . . . . . . . . . 5 11. Processing Model . . . . . . . . . . . . . . . . . . . . . . 5 11.1. Local Event . . . . . . . . . . . . . . . . . . . . . . 5 11.2. Incoming Causal Reference . . . . . . . . . . . . . . . 6 11.3. Recovery . . . . . . . . . . . . . . . . . . . . . . . . 6 11.4. Time Anchoring . . . . . . . . . . . . . . . . . . . . . 6 12. Example Flows . . . . . . . . . . . . . . . . . . . . . . . . 6 12.1. Snapshot and Resume . . . . . . . . . . . . . . . . . . 6 12.2. Transfer Pair . . . . . . . . . . . . . . . . . . . . . 6 12.3. Semantic Surface Mismatch . . . . . . . . . . . . . . . 6 13. Security Considerations . . . . . . . . . . . . . . . . . . . 6 14. Interoperability Considerations . . . . . . . . . . . . . . . 7 15. Relationship to the Broader Humotica Stack . . . . . . . . . 7 16. Future Work . . . . . . . . . . . . . . . . . . . . . . . . . 7 17. Questions for Future Revisions . . . . . . . . . . . . . . . 7 18. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8 19. References . . . . . . . . . . . . . . . . . . . . . . . . . 8 Appendix A. Acknowledgements . . . . . . . . . . . . . . . . . . 8 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 9 1. Status of This Memo This memo is an Internet-Draft working document derived from operational architecture notes, prototype implementations, and forensic delivery work produced in the Humotica / TIBET stack during May 2026. van de Meent Expires 10 November 2026 [Page 2] Internet-Draft TIBET Causal Time May 2026 It is intended to capture and formalize an already deployed structural property of TIBET rather than to introduce a greenfield timing model. This document is an initial public framing and substrate document intended to align distributed-systems theory, identity-bound execution, off-grid or degraded-network operations, and forward-only recovery semantics. 2. Problem Statement Many distributed systems continue to over-privilege wall-clock time. They assume that safe ordering, freshness, replay defense, and reversibility can be grounded primarily in synchronized UTC. That assumption is fragile under intermittent connectivity, NTP outage or misconfiguration, GNSS disruption, clock drift across edge nodes, compromised or ambiguous time authorities, and adversarial replay after restore or rollback. This document argues that causal order should be primary, wall-clock time auxiliary, recovery forward-only, and history non-rewritable. 3. Terminology Causal Time: The ordering of events by their dependency and sequence relationships, rather than by globally synchronized wall-clock timestamps. Forward-Only Causal Substrate: A substrate in which valid state evolution occurs only by appending new causally linked events. Logical Counter: A monotonic counter associated with event generation and ordering. Within TIBET this corresponds to the generation field. External Time Anchor: An observation of an external time-bearing source, recorded into the causal substrate as a signed event. Drift Record: A signed record describing observed offset between local time and an external anchor or between two time-bearing participants. Triage Fork: A forward-causal isolation path created in response to anomaly, mismatch, or uncertain continuity. van de Meent Expires 10 November 2026 [Page 3] Internet-Draft TIBET Causal Time May 2026 4. Design Goals The TIBET Causal Time Substrate is intended to preserve causal ordering without dependence on absolute time, support cryptographic identity binding of events, permit recovery and revocation without history rewriting, and remain meaningful under offline or degraded- network conditions. It is also intended to integrate with external time anchors, support replay-sensitive freshness checks, and surface time uncertainty honestly. 5. Model Overview TIBET encodes causal order through a set of existing structural primitives including append-only linkage, signatures, generation counters, and parent references. These map naturally onto a Lamport-style logical ordering model: happened-before pointers, tamper-evident order proof, authenticated event origin, logical counters, causal predecessors, and event-line roots. The important consequence is that TIBET already behaves as a causally ordered logical-time substrate. This document formalizes that fact. 6. Relation to Lamport and Related Work This document is directly aligned with Lamport's logical-time model and the later vector-clock tradition associated with Fidge and Mattern. TIBET extends that tradition by binding logical ordering to cryptographic identity, append-only lineage, and explicit fork, merge, and tombstone semantics. 7. Forward-Only Property The defining property of TIBET causal time is not merely that events are ordered, but that valid evolution occurs only by moving forward. Restore becomes fork rather than rewind, revocation becomes successor event rather than mutation, correction becomes amendment rather than overwrite, and cancellation becomes compensating action rather than erasure. 8. Event Classes van de Meent Expires 10 November 2026 [Page 4] Internet-Draft TIBET Causal Time May 2026 * ordinary application or system action events * fork or snapshot-reference events * merge or transfer-pair events * tombstone events * triage or quarantine events * external time-anchor events * drift-record events These classes are not all necessarily already standardized in TIBET registries, but they align structurally with the substrate described here. 9. External Time Anchors External time anchors provide auxiliary alignment between local causal order and broader time-bearing reference systems such as NTP, timestamping authorities defined by [RFC3161], Roughtime, GNSS, PTP, public ledger timestamps, or observed environmental anchors. External time anchors may improve alignment. They must not redefine already established causal order. 10. Drift and Alignment Clock drift is expected in real systems, especially edge systems and off-grid nodes. TIBET treats drift as a recordable condition, not as a collapse of ordering truth. Implementations should be able to represent locally observed time, externally anchored time, offset between them, uncertainty window, and validity scope of the observation. 11. Processing Model 11.1. Local Event When a local event is committed, the implementation increments or derives a monotonic generation value, binds the event to prior causal state, signs the event, and appends it. van de Meent Expires 10 November 2026 [Page 5] Internet-Draft TIBET Causal Time May 2026 11.2. Incoming Causal Reference When a remote or transferred event enters local reasoning, the implementation evaluates causal relation and derives successor progression in Lamport style as max(local generation, remote generation) plus one for any new local successor event that depends on both. 11.3. Recovery Recovery produces successor state by fork, compensation, revocation, or new forward-causal action. It must not pretend to restore the system to an earlier pre-committed causal state. 11.4. Time Anchoring When external time is sampled, the implementation may write an external-anchor event and may write drift information, but must not use the anchor to invalidate already committed causal order. 12. Example Flows 12.1. Snapshot and Resume In the TIBET model, a snapshot references a chain position and resume becomes a fork from that position. The new line advances with its own forward-only history. 12.2. Transfer Pair In TAT or TIBET Drop, transfer_out records sender-side causal commitment, transfer_in records receiver-side causal acknowledgement, and successor generation derives from the maximum of local and sender generation plus one. 12.3. Semantic Surface Mismatch If routing surface and sealed manifest differ, content may still be valid, but the causal substrate should treat the situation as anomaly and create a triage fork or isolation path. 13. Security Considerations This document assumes an attacker may replay previously valid artifacts, re-inject old state through backup or restore channels, manipulate wall-clock sources or exploit clock drift, rename or relabel artifacts outside sealed causal truth, or attempt destructive rollback semantics through operational tooling. van de Meent Expires 10 November 2026 [Page 6] Internet-Draft TIBET Causal Time May 2026 The forward-only causal model is specifically designed to reduce replay-after-restore, replay-after-revoke, backup injection, clock- spoofing ambiguity, drift concealment, and destructive rollback. The key invariant is that security-sensitive reversibility must be implemented as forward causal compensation, not as history rewrite. 14. Interoperability Considerations This substrate is designed to compose with JIS identity, UPIP continuity, TAT transfer flow, TBZ or ICC container semantics, and semantic routing surfaces. Interoperability therefore depends less on UTC agreement and more on shared causal encoding, verifiable linkage, explicit anchor semantics, and clear distinction between order and alignment. 15. Relationship to the Broader Humotica Stack Within the broader architecture, Turing answers what computes, Lamport-style causal time answers when in event order, JIS answers who is permitted, and semantic framing layers answer within what semantic frame a process is interpreted. TIBET occupies the causal-time substrate role while composing with the other axes. 16. Future Work * standardized external time-anchor token shape * standardized drift-record token shape * explicit uncertainty handling * causal freshness proofs for intermittently connected devices * zero-disclosure continuity proofs over long time horizons * alignment with RFC 3161, Roughtime, and public-ledger anchoring profiles 17. Questions for Future Revisions The following topics are non-blocking for the present -00 version and are recorded here to guide later discussion and interoperability work. van de Meent Expires 10 November 2026 [Page 7] Internet-Draft TIBET Causal Time May 2026 * whether drift should be standardized as its own token type or as a subclass of time-anchor event * whether external anchor trust levels should be formally graded * whether causal freshness should be defined as a reusable verification primitive * how uncertainty and stale-anchor conditions should be surfaced in operator tooling * whether some domains should require time-anchor presence while others permit purely local causal mode 18. IANA Considerations This document has no IANA actions in the present version. Future revisions may define registries for external time-anchor token shapes, drift-record token shapes, or causal freshness proof types, likely under Expert Review policy as described in [RFC8126]. 19. References [LAMPORT1978] Lamport, L., "Time, Clocks, and the Ordering of Events in a Distributed System", Communications of the ACM 21(7), 1978. [RFC3161] Adams, C., "Internet X.509 Public Key Infrastructure Time- Stamp Protocol (TSP)", RFC 3161, August 2001, . [RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for Writing an IANA Considerations Section in RFCs", BCP 26, RFC 8126, June 2017, . Appendix A. Acknowledgements The author thanks the Humotica team for editorial assistance, internal peer review, and operational tooling that made this substrate framing concrete rather than theoretical. The substrate framing also builds on the logical-time tradition established by [LAMPORT1978]. van de Meent Expires 10 November 2026 [Page 8] Internet-Draft TIBET Causal Time May 2026 The author also thanks Richard Barron of Red Specter Security Research for adversarial validation that helped sharpen the forward- only recovery property under realistic attack conditions. Author's Address Jasper van de Meent Humotica Netherlands Email: info@humotica.com URI: https://humotica.com/ van de Meent Expires 10 November 2026 [Page 9]