Privacy and data deletion
Collect less, know every copy, and make deletion real: propagate erasure through replicas, indexes, warehouses and backups, and use per-user keys for crypto-shredding.
25 min6 steps
By the end you can
- Apply data minimisation and storage limitation when deciding what to collect and keep
- Find every copy of personal data a deletion must reach, and order a deletion pipeline
- Calculate when the last copy of deleted data disappears, given processing time and retention
- Explain crypto-shredding with per-user keys, and what it does not cover
The safest data is data you never kept
A breach can only leak what exists. GDPR Art. 5 and 25: minimisation, storage limitation, protection by design and by default.
Keep every GPS point forever
- Years of home and work
- Must secure, disclose, delete
Keep weekly totals
- Feature still works
- Delete raw points after processing
Find every copy
The primary row is only the start. A deletion must reach every copy, and nobody has the list until it is written down.
A deletion pipeline
Deletion is a workflow with an owner, an audit trail and a deadline: one month, extendable by two (GDPR Art. 12(3)).
1
Verify requester
2
Mark deleted
3
Delete primary
4
Event to copies, acks
5
Audit log, confirm
Order a robust account-deletion pipeline.
- 1Mark the account deleted so no system processes or shows it any more
- 2Publish a deletion event that caches, search, the warehouse and processors consume and acknowledge
- 3Delete or anonymise the user's records in the primary stores
- 4Record completion in an audit log once every consumer has acknowledged, then confirm to the user
- 5Verify the request comes from the account holder
Backups and the last copy
Backups are immutable by design. Keep retention short and documented, re-apply deletions on restore, and treat erasure as done when the last copy expires.
Day 0
Request
Processing
Live stores purged
Longest retention
Last backup copy expires: done
Loading question…
Crypto-shredding
Crypto-shredding: encrypt each user's data under a per-user key, and destroy the key to erase every copy, including immutable backups (NIST SP 800-88). Plaintext, derived data, processors and key backups escape it.
Check your mastery
Score 80% or more.
Mastery check
3 questions on fresh variants. One attempt each, no time limit. Score 80% or more to master the lesson.
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