Privacy Policy
We built OTRUST so you do not have to trust us blindly. We minimize data by design and keep sensitive checks local when possible.
Last updated: July 4, 2026
TL;DR - Important points
Timestamp: your raw file stays local; only a cryptographic hash is transmitted.
Sign: choose local-hash mode or temporary encrypted upload with automatic deletion.
ID: commitment packages and verification metadata are stored, not raw ID photos.
Auth: hosted challenges, callback binding, and partner context with visible OTRUST processing.
History: your timestamp and Sign receipt lists stay in this browser only — not synced to the server or shared via public key.
Analytics: Plausible is used without cross-site tracking cookies.
Data Collection - Timestamp
For timestamping, OTRUST receives only record metadata needed for verification.
We do not collect
- Your original documents or media files
- Raw text content inside files
- Behavioral tracking profiles
We store
- SHA-256 hash and timestamp metadata
- OpenTimestamps receipt data
- Optional filename if you provide one
Browser-local history
Receipt lists in the Timestamp tool and browser extension are saved in your browser (localStorage or extension storage). They are not uploaded, not listed by public key on the server, and not passed in URLs. Clearing site data or using another browser or device starts with an empty list. Individual proof pages remain public if someone knows the receipt ID.
Data Collection - Sign
OTRUST Sign supports two operating modes:
Local-hash mode
- You share the document directly with signers
- OTRUST stores hash-based signing records only
- Best fit when the document should stay outside OTRUST
Temporary upload mode
- Encrypted storage with limited retention windows
- Automatic purge after selected retention period
- Signing metadata remains for verification
Permanent signature evidence
Signature records include document hash, signer-provided identifiers, cryptographic signatures, and timestamps so records can be verified later.
Browser-local signing history
Your list of documents you have signed is stored in this browser only, the same way as timestamp receipts. It is not exposed as a server-side list tied to your key.
Data Collection - ID
The Proof Lab creates self-attested age and income range proofs locally. It does not inspect identity documents or issue identity credentials.
We do not receive
- The private date of birth or exact income used in a range proof
- Raw ID images or selfies through the active Proof Lab flow
- Reusable biometric templates
We store
- The Groth16 proof and its public signals
- The public commitment and proof type
- Server-derived verification and submission metadata
Local processing model
The private value is used by the browser to generate a proof and is excluded from the publish request. A valid proof does not establish that the private value came from a trusted issuer.
Data Collection - Auth
- Challenge data: client identifier, redirect URI, state, and expiry for short-lived Auth sessions.
- Verification result: trusted issuer credential status and callback tokens bound to the challenge, state, redirect URI, and expiry.
- Availability: production Auth challenges remain disabled until a trusted issuer is configured.
- Partner context: approved branding fields for hosted pages, without arbitrary partner scripts.
Third-Party Services
| Service | Purpose | Data Shared |
|---|---|---|
| OpenTimestamps | Bitcoin anchoring | Hash-based receipt data |
| Bitcoin network | Immutable anchoring | Aggregated timestamp commitments |
| Plausible | Privacy-friendly analytics | Aggregate page analytics without cross-site cookies |
Your Rights
- Access: public ID records can be checked independently.
- Correction: contact us if metadata appears incorrect.
- Deletion limits: permanent ID records cannot always be removed without breaking verification integrity.
- Transparency: implementation details and public repos are available for review.
Policy Changes
We may update this policy as services evolve. The date at the top reflects the latest version.
Questions?
Email: privacy@otrust.eu