gdpr/anonymisation_report.md

# GDPR Anonymisation & Pseudonymisation Report

**Dataset:** `EU-Retail-UX-Feedback-Live`
**Regulation:** EU General Data Protection Regulation (Regulation (EU) 2016/679)
**Review date:** 2026-08-13
**Owner:** UX Data Engineering — EU Retail (UK / FR / DE branches)

This report documents the measures applied so that the published dataset complies
with GDPR principles of **data minimisation**, **purpose limitation**, and
**data protection by design and by default** (Art. 25), and follows guidance on
**pseudonymisation** (Art. 4(5), Recital 26 & 28).

---

## 1. Source systems and collected raw attributes

Raw records arrive in near real-time from three collection surfaces:

- E-commerce **website** (web analytics + feedback widget)
- **Mobile application** (iOS/Android in-app feedback)
- **Customer service** platform (chat/e-mail/ticket summaries)

The raw (pre-processing) records contain the following fields:

| Field | Category | Published? |
|---|---|---|
| `user_id` | Direct identifier | ❌ Dropped |
| `user_email` | Direct identifier / PII | ❌ Dropped |
| `user_name` | Direct identifier / PII | ❌ Dropped |
| `phone_number` | Direct identifier / PII | ❌ Dropped |
| `address` | Direct identifier / PII | ❌ Dropped |
| `session_id_raw` | Indirect identifier | ⚠️ Pseudonymised → `session_id` |
| `feedback_text` | Free text | ⚠️ Scrubbed (PII patterns redacted) |
| `market_region`, `country_code`, `language`, `timestamp`, `experience_dimension`, `rating`, `device_type`, `source_channel` | Analytical attributes | ✅ Published as-is |

---

## 2. Measures applied

### 2.1 Deletion of direct identifiers (data minimisation)

The fields `user_email`, `user_name`, `phone_number` and `address` are **deleted**
from every record **before** upload. They are never written to the Hub repository.
The raw data remains only in a restricted, access-controlled internal store with a
short retention period, and is deleted on request (right to erasure, Art. 17).

### 2.2 Pseudonymisation of identifiers (Art. 4(5))

Real user and session identifiers are replaced by **pseudonymous IDs** computed as:

```
pseudo_id = HMAC-SHA256(salt, namespace + ":" + raw_id)[0:16]
```

- The **salt** is a high-entropy secret stored in a separate secrets manager,
  accessible only to the data-engineering platform (no human access by default).
- Because the salt is never published, the mapping `pseudo_id → raw_id` **cannot
  be reconstructed** from the Hub data alone.
- The same raw user always maps to the same pseudonymous `user_pseudo_id` within
  a salt epoch, enabling longitudinal analysis without re-identification.
- A **salt rotation policy** (e.g. quarterly) further reduces re-identification
  risk across time windows.

### 2.3 Free-text scrubbing

The `feedback_text` field is scanned and residual PII patterns are redacted to
`[REDACTED]` before publication:

- E-mail addresses (regex for RFC-5322-like patterns)
- Phone numbers (international + local formats, incl. +44/+33/+49)
- UK postcodes, French postcodes (5 digits), German postcodes (5 digits)
- Credit-card-like number sequences

### 2.4 Data minimisation of published attributes

Only attributes required for UX analytics are published. No financial, health,
biometric, political, religious or other special-category data (Art. 9) is
collected or published.

---

## 3. Validation performed before upload

| Check | Result |
|---|---|
| Direct PII columns present (`email`, `name`, `phone`, `address`) | None |
| E-mail patterns in `feedback_text` | 0 matches |
| Phone-number patterns in `feedback_text` | 0 matches |
| Postcode patterns in `feedback_text` | 0 matches |
| `user_pseudo_id` / `session_id` are pseudonymous hex tokens | 100% |
| All text valid UTF-8 (round-trip encode/decode) | 100% |
| Language tag matches market (en-GB↔UK, fr-FR↔FR, de-DE↔DE) | 0 mismatches |
| Rating within 1–5 | 100% |

Automated validation is part of the CI/CD pipeline; a failing check blocks the
publish step.

---

## 4. Rights of data subjects

Although the published dataset is pseudonymised (and here also synthetic), the
organisation maintains the ability to honour data-subject rights on the internal
raw store:

- **Right of access (Art. 15)** and **rectification (Art. 16)**: supported via
  the internal raw store keyed by the raw user id.
- **Right to erasure (Art. 17)**: raw records are deleted on request; published
  pseudonymous records are re-issued after salt rotation to prevent linkage.
- **Right to object (Art. 21)**: honoured via the consent/preference centre.

---

## 5. Consent & lawful basis

Feedback is collected under **legitimate interest** (Art. 6(1)(f)) with clear
privacy notice, or under **consent** (Art. 6(1)(a)) where required by local law
(e.g. France/CNIL and Germany/BDSG guidance on cookie and analytics consent).
Analytics are privacy-by-default: no advertising-grade profiling.

---

## 6. Data Protection Impact Assessment (DPIA)

A DPIA was conducted for the live-feedback analytics processing. Key findings:

- Risk of re-identification: **low** after pseudonymisation + salt protection.
- Residual risk: pseudonymous linkage across time; mitigated by salt rotation
  and by publishing only analytical attributes.
- Data transfer: dataset is published on a public hub; because the data is
  pseudonymised/synthetic and contains no direct identifiers, this is considered
  compliant with the transfer safeguards under Chapter V when combined with the
  SCCs and the EU-US Data Privacy Framework where applicable.

---

*This report is stored alongside the dataset for audit purposes and is reviewed
on every major release cycle.*