@zanii/retention

Provable data-deletion attestations for GDPR Art. 17 (right to erasure) and similar. You can't cryptographically prove an absence, so a deletion proof is a signed, timestamped, tamper-evident attestation — which is exactly what a Zanii receipt is. This builds a well-structured data.retention.<action> receipt that references the erased subject by a salted commitment, never raw PII.

npm install @zanii/retention

Usage

import { buildRetentionAttestation } from '@zanii/retention';
import { ZaniiAgent } from '@zanii/sdk';

const agent = new ZaniiAgent({ /* … */ });

const { target, payload, salt } = buildRetentionAttestation({
  subject: 'user:42',            // committed, never stored raw
  policy: 'gdpr-erasure',
  scope: ['profile', 'orders'],
  executedAt: new Date().toISOString(),
  method: 'hard-delete',
});

await agent.record({ target, payload });   // anchored, tamper-evident proof of deletion
// keep `salt` to later prove the attestation was about user:42, without it ever
// being in the receipt:  verifySubject('user:42', salt, payload.subject_commitment)

The receipt leaks nothing about who was erased. When a regulator asks, reveal the salt for the specific subject and verifySubject proves the match against the immutable, anchored entry. verifyRetention(payload) structurally validates an attestation.

Changelog

• 0.2.0 — added buildRetentionHold / verifyRetentionHold — the inverse attestation: prove records were kept to a retain_until (UAE Companies Law / FTA 5-yr retention).
• 0.1.0 — initial release: buildRetentionAttestation, verifyRetention, commitSubject, verifySubject.

License

Apache-2.0.