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🔒 Privacy Policy

Effective Date: March 25, 2026  ·  Last Updated: June 16, 2026

1. Introduction

XPRV OÜ ("we," "our," or "us") operates the StampHash platform. This Privacy Policy explains what personal data we collect, why, the legal basis under GDPR (EU) 2016/679 and equivalent UK / US state laws, and your rights. By using StampHash you acknowledge you have read this policy.

2. Data Controller

3. What We Collect & Why

3.1 Evidence & File Data

• SHA-256 hash of your file — this hash, and only this hash, is embedded in a Bitcoin transaction (“OP_RETURN”). It is permanent and cannot be deleted.
• Encrypted file — your file is encrypted client-side with your PIN before upload. The server stores only encrypted ciphertext; only you hold the key.
• Encrypted metadata — capture details (GPS, device, original filename, timestamp) are encrypted on your device with your PIN and stored only as ciphertext. We cannot read them; only you can decrypt them, and they are not written to the blockchain.

Legal basis: Performance of a contract (Art. 6(1)(b) GDPR) — these are the core deliverables of the Service.

3.2 Precise GPS Location (optional)

If you grant location permission, your latitude/longitude is included in your evidence metadata, which is encrypted on your device with your PIN before it is uploaded. Your GPS data is not written to the Bitcoin blockchain, and we never store it in readable form — the server holds only ciphertext that only you can decrypt. Because it is not on-chain, your location data is not subject to blockchain permanence: the encrypted evidence file is deleted from our servers after the retention period (see §4), and you control your own copy. GPS is optional — you may deny permission and still use the Service. We do not collect or link your name, email, or account.

Legal basis: Explicit consent (Art. 6(1)(a) GDPR). Consent is freely given, specific, informed, and unambiguous — you may deny GPS permission and still use the Service.

3.3 Device Information

Basic device details (such as platform and browser family) may be included in your client-side-encrypted metadata to support the evidentiary record. Like your GPS data, this is stored only as ciphertext that only you can decrypt, and it is not written to the blockchain. We do not store your full user-agent string or IP address within your evidence records.

Legal basis: Legitimate interests (Art. 6(1)(f) GDPR) — providing authenticated evidence metadata — balanced against your interests; the data is encrypted under your sole control and you can review it on the Capture screen before notarizing.

3.4 Payment Data

Mainnet payments are processed by Stripe, Inc. We do not receive or store your card number, CVV, or full billing details. We receive only a payment confirmation token. Stripe acts as an independent data controller for payment data; see Stripe's Privacy Policy.

Legal basis: Performance of a contract (Art. 6(1)(b) GDPR).

3.5 Technical & Server Logs

• Limited request logs (timestamps, API usage, and IP address) are retained transiently for security and abuse prevention. IP addresses are not stored within, or linked to, your evidence records.

Legal basis: Legitimate interests (Art. 6(1)(f) GDPR) — security and abuse prevention.

3.6 Local Device Storage

We store your evidence history (transaction IDs, file names, hashes) in your browser's localStorage. This data never leaves your device and is under your control. You can clear it at any time from the "My Evidence" screen.

Legal basis: Consent via the first-use notice displayed when you first access the app (ePrivacy Directive / UK PECR).

4. Data Retention

• On-chain data (SHA-256 hash only): Permanent — cannot be deleted. GPS, device, and filename are not placed on-chain.
• Encrypted evidence file on server: 60 days, then automatically deleted. Encrypt and download your own copy before then — we cannot recover a deleted file. You will see the remaining time when you search for your evidence.
• Evidence record (hash, transaction ID, and your encrypted metadata blob): Retained so the proof remains verifiable. The metadata remains encrypted and decryptable only by you.
• Server access logs: Retained transiently for security.
• Payment records: 7 years (financial regulations).
• localStorage on your device: Until you clear it.

5. International Transfers

Our servers are located in the EU (Estonia). Blockchain broadcast APIs (mempool.space, Blockstream) and Stripe (US) may process your data outside the EU under Standard Contractual Clauses (SCCs). Stripe holds a current EU–US Data Privacy Framework certification.

6. Your Rights (GDPR / UK GDPR)

Where technically feasible you have the right to: access, rectification, erasure (except on-chain data), restriction, portability, and to object to processing based on legitimate interests. To exercise any right contact privacy@stamphash.app. You may also lodge a complaint with your national supervisory authority (e.g., the Estonian Data Protection Inspectorate for EU residents, the ICO for UK residents).

7. California Residents (CCPA / CPRA)

We do not sell or share personal information for cross-context behavioural advertising. California residents may request disclosure of categories of personal information collected and request deletion (except for on-chain records). Contact privacy@stamphash.app.

8. Children

StampHash is not directed to children under 16. We do not knowingly collect data from anyone under 16. If you believe a child has provided data, contact us immediately.

9. Changes to This Policy

Material changes will be notified by updating the "Last Updated" date and a notice inside the app.

10. Contact

Privacy enquiries: privacy@stamphash.app

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📋 Terms of Service

Effective Date: March 25, 2026  ·  Last Updated: June 16, 2026

1. Agreement

By using StampHash ("Service") you agree to these Terms. If you disagree, do not use the Service.

2. Service Provider

3. Description of Service

StampHash provides blockchain-based evidence notarization: capturing files, computing cryptographic hashes, and anchoring those hashes permanently on the Bitcoin blockchain via OP_RETURN transactions.

4. User Responsibilities

• You must not upload illegal, harmful, or copyright-infringing content.
• You are solely responsible for the content you notarize.
• You warrant you have the legal right to notarize the submitted content.
• You understand that blockchain records are permanent and irrevocable.

5. Payments

Mainnet notarizations require a one-time fee processed through Stripe. Test-net notarizations are free. Payments are non-refundable once a Bitcoin transaction has been broadcast. If you are charged but no transaction is confirmed due to a technical failure, contact support@stamphash.app within 48 hours for a review.

6. Blockchain Immutability

7. Privacy

Please read our Privacy Policy for information on how we handle your data.

8. Disclaimers

The Service is provided "as is" without warranties of any kind. We do not guarantee specific blockchain confirmation times or uninterrupted service availability.

9. Limitation of Liability

To the fullest extent permitted by law, XPRV OÜ's liability is limited to amounts paid for the Service in the 12 months preceding a claim. We are not liable for indirect, incidental, or consequential damages.

10. Governing Law; Arbitration; Venue

Governing law. These Terms, and any dispute or claim arising out of or relating to them or to the Service, are governed by the laws of the State of New York, USA, without regard to its conflict-of-laws rules.

Mandatory local law. XPRV OÜ is established in Estonia. Nothing in these Terms removes or limits any protection afforded to you by the mandatory provisions of Estonian or European Union law that apply because of where we are established (including mandatory consumer-protection and data-protection law). To the extent any such mandatory provision conflicts with New York law, that mandatory provision controls, but only to the minimum extent required.

Informal resolution. Before commencing arbitration, the parties will attempt in good faith to resolve any dispute for thirty (30) days after written notice is sent to support@stamphash.app.

Binding arbitration. Except as limited by the mandatory-law provision above, any dispute not resolved informally shall be finally settled by binding arbitration administered by the American Arbitration Association (AAA) under its Commercial Arbitration Rules (or, where applicable, its Consumer Arbitration Rules). The seat, venue, and location of the arbitration shall be New York, New York, USA; the arbitration shall be conducted in English before a single arbitrator; and judgment on the award may be entered in any court of competent jurisdiction.

Court venue. For any matter not subject to arbitration (for example, to compel arbitration or to enforce an award), the parties submit to the exclusive jurisdiction and venue of the state and federal courts located in New York, New York, except where mandatory law gives you the right to bring proceedings in your country of residence.

Individual basis. Disputes will be resolved only on an individual basis; class, collective, or representative actions are not permitted, except where such a waiver is prohibited by mandatory law.

This Section is a contractual term, not legal advice. If you are a consumer in the EU/EEA, some of the above may not apply to you to the extent local mandatory law provides otherwise.

11. Changes

We may update these Terms. Material changes will be notified inside the app. Continued use constitutes acceptance.

12. Contact

Legal enquiries: support@stamphash.app

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