Prompt 02A - Cryptography, privacy claims, and trust-boundary gate

Mode

Start in Plan mode. Small corrective code changes are allowed only after the architecture decision and test plan are approved.

Required context

• Current subject, admin, import, results, PDP, and export code
• All backend handlers for keys, envelopes, responses, results, metrics, verification, PDP, resealing, and wrap-up
• Logging, tracing, analytics, proxy, worker, and support-access configuration
• Existing privacy/security copy
• Data-classification and anonymity wiki pages

Prompt

Establish the actual Capablio trust model and make code, UI, documentation, and marketing consistent with it.

1. Trace sensitive data end to end

Create a data-flow diagram and table for:

• private and public keys
• sealed envelopes
• individual scores
• consented_scores
• free-text comments
• importance rankings
• imported PDF plaintext
• result metrics
• PDP answers and goals
• exports and rendered HTML

For every transition record process, storage, transport, encryption state, retention, logging risk, and authorized readers.

2. Audit all private-key handling

Find every request body, URL, worker message, log, trace, analytics event, cache, and support path that can contain a private key or equivalent decryption secret.

Treat a private key in a query string as a release blocker.

Do not accept the label "client-side encryption" as proof of a zero-knowledge service if the private key reaches a server.

3. Reconcile plaintext score handling

Document why multi-rater consented_scores exist, whether they are linkable to a respondent, how they are aggregated, when raw values are deleted, and how minimum-group thresholds are enforced.

Decide whether the product is:

• subject-private with client-side aggregation/decryption
• service-readable under a clearly disclosed model
• tenant-recoverable under approved controls
• a supported combination of explicitly named modes

Do not mix these modes in one vague promise.

4. Select and document the supported architecture

Produce ADRs for:

• key generation and custody
• device storage
• backup/recovery
• additional devices
• leavers
• key rotation and resealing
• server-side aggregation requirements
• import processing
• report generation
• PDP processing
• customer-managed keys if planned

If subject-private mode is selected, private keys must not be transmitted to Capablio services. Move decrypt/derive operations to the approved client or trusted boundary.

5. Correct unsafe interfaces

At minimum:

• remove private secrets from query strings
• remove or redesign APIs that require a subject private key
• add log/trace redaction and tests
• review sessionStorage and XSS implications
• define CSP and trusted script policy
• sandbox or replace server-generated srcdoc report rendering
• sanitize all untrusted people, comment, and imported content
• review key-file provisioning language and custody

6. Correct product claims

Create an approved claim matrix:

Update UI, marketing, documentation, emails, and sales/demo content. Remove unsupported phrases immediately behind a feature/content flag if necessary.

7. Tests and evidence

Add:

• automated search/test preventing private keys in URLs, logs, analytics, and error payloads
• API contract tests for every encryption boundary
• cross-tenant and support-access negative tests
• XSS tests with key material present
• aggregation/anonymity tests
• recovery and device migration tests
• browser and CSP compatibility tests
• an independent security-review checklist

Required outputs

wiki/internal/security/cryptographic-data-flow.md
wiki/internal/security/key-custody-and-recovery.md
wiki/internal/security/plaintext-score-processing.md
wiki/internal/security/threat-model.md
wiki/internal/adr/ADR-crypto-trust-mode.md
wiki/shared/privacy-claim-matrix.md
wiki/internal/product/crypto-migration-plan.md

Exit gate

Do not proceed with a zero-knowledge, keys-never-leave-browser, or server-cannot-read claim until the selected architecture, implementation, tests, and documentation all support it.