# The legal basis for retaining audit facts against an erasure request has been assumed, never established

## What is true

`audit-core` holds audit evidence across tenants, targets `R2` on the Tenancy Posture retention ladder, and has declared `R4` — verified erasure — unreachable by design. The technical reasoning is sound and documented (`audit-core/docs/erasure-and-audit.md`, framework Decision 4.5.3): crypto-shredding would destroy the evidence the service exists to hold, and their integrity chain commits to a SHA-256 of the cleartext record, which survives key destruction as a confirmation oracle against low-entropy audit rows. Destroying a key does not erase content a surviving commitment can still be tested against.

The consequence is that if an Article 17 request arrives naming a data subject in the audit trail, `audit-core` has no mechanism. The answer would rest on audit evidence being exempt — legal obligation, or legitimate interest in fraud and security investigation.

Those grounds are ordinary. Nobody in this estate has actually reached them. `audit-core` routed the question here on 2026-08-18 rather than absorbing it, saying plainly that they are not competent to answer it and that they have been assuming it. §19.11 of the framework says the same in its own words: the legal basis for retaining audit facts remains a risk/legal question outside the framework.

## Why this repo owns it

This is the first finding where `fix_owner` is `risk-nexus`.

`INTENT.md` moved regulatory intake here from `policy-nexus` on 2026-08-17, precisely because deciding what a rule demands of us is a judgement about risk rather than an act of publishing. `audit-core` routed it by both available routes and asked for an owner rather than an opinion. Refusing it would be this repo declining its own remit.

What this repo owns is the record: what the source says, when, and what therefore is or is not established. It does not own legal advice — `INTENT.md` is explicit — and it does not own the redesign. If the basis does not hold, `audit-core` owns encrypt-then-hash at accept time, and that is not retrofittable onto events already accepted.

## The three questions, as asked

1. On what basis does the estate retain personal data inside audit records against an erasure request, and does that basis hold for the categories `audit-core` stores?
2. Does it hold across the full 30-day recoverable window and beyond, given that at `P1` the real erasure horizon is the maximum across every co-resident on `platform-pg`, not the value `audit-core` declares?
3. If it does not hold, `R4` is urgent rather than theoretical, and the answer is a substantial redesign with a long lead time.

## Register ruling — 2026-08-19

`medium` today (`I3` × `L2`), `high` at production, `public`, escalated on trigger 2.

`I3`: an unmet retention obligation in the audit store crosses from a technical question to an obligation with an outside counterparty, and the remediation is a non-retrofittable redesign rather than a patch. `L2`: no request has arrived and the estate holds no real data subject's records yet, but the trigger is somebody else's to pull and needs no foothold here.

`production_rescore: true`. The likelihood of an Article 17 request is a function of having real users; that is exactly what production means.

Escalation, trigger 2 — "creates or reveals an obligation with an outside counterparty". It reveals one. The estate cannot decide unilaterally that this obligation is small, and the operator is the only party who can commission an answer that is more than an assumption. The ask is narrow: authorise someone to establish the basis, or record that the estate knowingly runs on the assumption and for how long.

Disclosure `public`. Nothing here shortens a path to a defect: it is a question about a legal basis, published as a question. `audit-core`'s technical reasoning is already written down and worth reading.

## How it got here

Ruled a note on 2026-08-19 (`RISK-N-0002`) on the reasoning that no obligation exists yet. That ruling was made without reading `audit-core`'s message, which had been in this repo's inbox since 2026-08-18 and asks specifically for an owner. The note was wrong on the second floor test: recording this does change a decision, because the redesign it might force cannot be retrofitted and therefore has to be decided early or not at all.

`RISK-N-0002` is superseded by this record.

## Reviews

- 2026-08-19 — promoted from note, graded, escalated. Open at review: has the basis been established or the assumption recorded; has anything changed about what categories `audit-core` stores.

## Suggested disposition — 2026-08-20, proposed by risk-nexus

Offered because this repo owns the finding and the operator asked for a direction. It is not legal advice, and this repo cannot make it into one: what follows is a route to an answer and a hedge against the answer being no.

### The reframe: the expensive thing is not the legal question

`audit-core` asks whether the exemption holds. That question is cheap to answer badly and expensive to answer properly, and the temptation is to schedule the proper version and wait.

But the cost of a "no" is not fixed — it grows daily. The remedy they name, encrypt-then-hash at accept time, cannot be retrofitted onto events already accepted. Every day the estate accepts events under the current scheme, the un-erasable set grows by one day. So the decision that actually needs taking now is not "is it exempt" but "do we keep manufacturing records we could never erase while we find out".

That splits the finding into two decisions with very different prices.

### 1. Establish the basis internally, now, for the cost of an afternoon

Not a legal opinion — a written determination that says which ground is being relied on, for which category of data, and for how long. Today the estate has no such document; that is the whole finding.

The shape it should take, per category of personal data in the audit trail:

Category | Likely ground | The part that is actually arguable
--- | --- | ---
Operator and agent identifiers | Art 6(1)(f) legitimate interest in security, with Recital 49 squarely on point | little — this is the ordinary case
Counterparty or end-user identifiers in event payloads | Art 17(3)(e), defence of legal claims; Art 6(1)(f) | duration, not existence
Commercial records that happen to pass through audit | Art 17(3)(b) plus German §257 HGB / §147 AO retention | scope — retention duties cover books and invoices, not application logs generally

Where such determinations usually fail is not the ground. It is the retention period: a blanket "we keep audit forever under legitimate interest" is much weaker than "we keep these fields for N months because X". That lands precisely on `audit-core`'s question 2 — the real horizon being the maximum across every co-resident on `platform-pg` rather than the declared value.

Recording the determination converts an assumption into a position that can be argued with. That is what this register exists to produce, and it does not require a lawyer to write down.

### 2. Stop the un-erasable set from growing — a cheaper hedge than the redesign

`audit-core`'s stated obstacle is precise and correct: their chain commits to `SHA-256(cleartext)`, audit records are low-entropy, so the retained hash survives key destruction as a confirmation oracle. Guess, hash, compare.

The oracle exists because the commitment is over cleartext with no secret in it. A keyed commitment removes it: replace the digest with an HMAC (or a hash over record plus a high-entropy per-subject salt) where the key or salt lives outside the audit store and is destroyable per subject.

What that buys, and why it is cheaper than the redesign they costed:

- Destroying the per-subject key makes the commitment untestable — no guess can be confirmed. That is crypto-shredding restored, which their analysis correctly found unavailable under a plain hash.
- The integrity chain still verifies. It chains over commitment values, and those persist after key destruction; what is lost is the ability to re-derive a commitment from cleartext, which is exactly what erasure means.
- It is a change at accept time only. No re-processing of stored events, no new storage layer, no change to the read path.

This is a suggestion to `audit-core`, not an instruction, and they own whether it is sound — they know their chain and this repo does not. The claim worth testing with them is narrow: does a keyed commitment restore erasability without breaking chain verification? If yes, the expensive redesign becomes a contingency rather than a plan, and the daily accrual stops.

### 3. Buy the real answer only when something triggers it

An external determination costs money and needs a real question. Propose three triggers, any of which fires it:

- the estate first holds a real person's data;
- a counterparty contract requires a stated erasure position;
- an actual Art 17 request arrives.

Until one fires, the internal determination plus the hedge is a proportionate posture, and `severity_at_production: high` plus `production_rescore: true` already guarantee this is re-read before production completes.

### What this repo would record if the operator agrees

`status: accepted` with the determination attached, `escalation` answered as `rule`, and the review kept at 90 days. The finding stays open and visible until the determination exists — an accepted risk with no written basis is the same assumption it started as, wearing a different word.

### Also worth saying, because it is the cheapest fix of all

Every field of personal data that never enters the audit trail is a field with no erasure question. Where an opaque subject identifier would carry the same evidentiary weight as a name or an address, the identifier is strictly better, and that is a `audit-core` design choice available today at no legal cost.

## Operator decision — 2026-08-20: minimise the identity, keep the accountability

The custodian ruled on what goes into an audit record, which is the half of this finding that shrinks the question rather than answering it:

1. Opaque subject identifiers are preferred. Where an opaque id carries the same evidentiary weight as a name or an address, it is the id that goes in.
2. Agent identifiers where possible. Agents act; attribute to the acting agent identity rather than to a person behind it.
3. Operator credentials only where necessary. Not as a convenience, not as a default — where the record genuinely requires the operator.
4. Policy decisions are tracked to the responsible party. Accountability is preserved by linking a decision to who is answerable for it, not by retaining personal data in the record itself.
5. Zone guarantees may raise the floor. If a zone establishes additional privacy, pseudonymity or anonymity guarantees, those apply — the current level is not a permanent ceiling. That work is `zone-engine`'s (`ZONE-WP-0001`), and this finding should be re-read when a zone lands one.

Why this is more than a preference. Personal data that never enters the audit trail has no erasure question, no exemption to establish, and nothing to argue about with a regulator. Points 1-3 shrink the population the legal basis has to cover; point 4 is what stops that shrinking from costing accountability, which is the usual objection to minimising an audit log.

It also changes the shape of the accrual problem. The un-erasable set still grows daily, but each day's records now carry less that would need erasing — so the cost of a "no" answer falls with every event accepted under the new rule rather than rising.

What is still outstanding, and stays escalated:

- The written determination of the retention basis — which ground, for which category, for how long. `risk-nexus` owns writing it; it needs no further authorisation and is scheduled into the next workplan.
- The trigger list for buying an external answer (first real person's data, first counterparty contract requiring a stated position, first Art 17 request). Proposed, not yet ruled on.

The escalation is therefore `partially-answered`, not closed. `make check` will keep listing it.

Routed to `audit-core` on 2026-08-20, together with the keyed-commitment question — which remains theirs to judge, because they know their chain.

## The determination exists — 2026-08-20

`docs/regulatory/RISK-REG-0001` (`audit-retention-basis.md`). The estate now has a written position rather than an assumption, which was this finding's substance.

What it says, in short: Art 6(1)(f) with Art 32 for operator and agent audit records; Art 17(3)(e) for records evidencing a counterparty transaction; Art 17(3)(b) only where a commercial or tax retention duty independently applies, and not extended to application logs generally.

The weak part is duration, not existence, and the record says so rather than sounding confident. A position of the form "we keep audit forever because it is audit" is the one that fails; a period per category is what holds. The estate does not have one yet, and the reason is `audit-core`'s own question 2 — at `P1` the real horizon is the maximum across every co-resident on `platform-pg`, not the declared value. That infrastructure fact is the most likely point of failure in the whole position.

The operator's minimisation ruling improves this materially: it shrinks the category whose retention is hardest to justify, leaving mostly the row where the ground is strong. A weak argument avoided by holding less data beats a strong one relied upon.

The finding stays open. What remains is a retention period per category, which waits on the co-residency horizon, and the trigger list for buying an external determination. The record is reviewed every 90 days with this finding, or immediately on any trigger.

- 2026-08-20 — not clean: The determination now exists: RISK-REG-0001 states the grounds per category and names duration as the weak point. Cadence instant → instant; checked again immediately.

## Operator decision — 2026-08-20: no external determination, and a policy set instead

Ruled: the estate will not buy an external determination while it is building. The internal determination (`RISK-REG-0001`) stands as the recorded position, and the finding moves to `accepted` — deliberately carried, with a named accepter and a condition that ends it.

That is not the same as the trigger list being rejected. The triggers survive as what ends the acceptance: a real person's data, or a counterparty requiring a stated position. What was declined is spending money in advance of either.

The compensating control is the thing that makes this defensible. Rather than defer the question, the operator directed that the estate define and keep a set of legal policies for reuse, because future work contexts will need specific positions in place and should retrieve them rather than research them.

`docs/regulatory/policies/` now catalogues thirteen, keyed by activation condition. Two of them turned out to be already active and unowned: commercial and tax retention (`RISK-POL-0009`), and the e-invoicing receiving obligation (`RISK-POL-0012`), live since 2025 with no system in the estate named as the receiving point.

Finding an unnoticed live obligation in the first hour of building the catalogue is the argument for having built it. The reason this repo exists is that regulation was previously "consulted and discarded"; a set that answers "what applies if we do X" before anyone does X is the opposite of that.

Still open under the acceptance, and unchanged by this ruling: `audit-core` on whether a keyed commitment restores erasability, and the `platform-pg` co-residency horizon that decides whether the stated retention periods are achievable. An accepted risk still gets checked.

- 2026-08-20 — not clean: Trigger list ruled: no external determination in build mode; accepted with the legal policy set as the compensating control. Cadence instant → instant; checked again immediately.