Terms of Service

Last updated: April 2026

1. Acceptance of Terms

By accessing or using VaultBytes services ("Services"), you agree to be bound by these Terms of Service ("Terms"). If you do not agree to these Terms, do not use our Services.

2. Description of Services

VaultBytes provides secure AI explainability and FHE validation services, including:

  • CipherExplain API — encrypted SHAP explanations for linear classifiers via a JSON REST API
  • FHE Testing Oracle — adversarial differential precision testing for fully homomorphic encryption circuits
  • Related SDKs, tools, and documentation

3. API Keys and Account Security

Access to the CipherExplain API requires an API key ("Key") issued by VaultBytes. You agree to:

  • Keep your Key confidential and not share it with third parties
  • Use your Key only for your own authorised workloads
  • Notify us immediately at b@vaultbytes.com if your Key is compromised
  • Rotate your Key promptly via POST /keys/rotate if you suspect unauthorised use
  • Accept responsibility for all API calls made under your Key

API keys are stored as SHA-256 hashes. We cannot retrieve the raw value of your Key. If lost, you must rotate to obtain a new one.

4. Tiers, Quotas, and Billing

4.1 Service Tiers

The CipherExplain API is offered in three tiers:

  • Free — 50 SHAP explain calls/month, 3 oracle runs/month, 1 model slot. No charge.
  • Developer — 5,000 explain calls/month, 500 oracle runs/month, 10 model slots. Billed monthly.
  • Enterprise — 50,000 explain calls/month, 5,000 oracle runs/month, unlimited model slots. Billed monthly or annually.

4.2 Quotas

Quotas reset on the first day of each calendar month (UTC). Unused quota does not roll over. Calls that exceed your monthly quota will be rejected with HTTP 429. We do not automatically upgrade your tier or charge overage fees.

4.3 Payments

Paid tiers are billed in advance via Stripe. By subscribing, you authorise VaultBytes to charge your payment method on a recurring basis. All prices are exclusive of VAT or applicable taxes, which will be added at checkout where required by law.

4.4 Cancellation

You may cancel your subscription at any time via the self-serve Stripe Customer Portal, accessible from the pricing section at vaultbytes.com/cipherexplain using your API key. There are no cancellation fees. Upon cancellation:

  • Your API access continues until the end of the current billing period.
  • Your account reverts to the Free tier at the end of that period.
  • Your registered models are retained on the Free tier (subject to the 1-slot limit — you may need to delete models to stay within the free limit).
  • Cancellation is processed immediately via Stripe — no manual steps required.

4.5 Refunds

Monthly subscriptions are non-refundable once a billing period has started. Annual subscriptions may be refunded on a pro-rata basis within 14 days of purchase if no API calls have been made in the new period. Contact b@vaultbytes.com to request a refund.

5. Acceptable Use

You agree not to:

  • Use the Services for any unlawful purpose or in violation of any applicable regulation
  • Attempt to reverse-engineer, scrape, or extract our FHE circuit implementations or SHAP computation methods
  • Circumvent rate limits, quotas, or access controls
  • Share, resell, or sublicense API access to third parties without written permission
  • Interfere with or disrupt the Services or servers
  • Use the Services to process data you do not have lawful authority to process
  • Infringe on any intellectual property rights

6. Model Data and Privacy

6.1 What You Send Us

When registering a model via POST /models/register, you transmit only model weight coefficients and intercept values — no training data, no raw personal data. You represent that you have the right to transmit these weights.

6.2 What We Store

We store your model weights in memory and in an encrypted database solely to serve your explain requests. We do not use your model weights to train our own models or share them with third parties.

6.3 Input Vectors

Feature vectors submitted to /explain or /explain_raw are processed in memory and are not persistently stored. Usage metadata (call count, model ID, feature count, timestamp) is retained for quota tracking and billing.

7. Audit Reports

PDF audit reports generated via POST /report are produced solely from the benchmark JSON you supply. VaultBytes makes no representation that these reports satisfy any particular regulatory, legal, or compliance requirement. You are responsible for determining whether a report is suitable for your intended purpose, including any regulatory filing.

8. Intellectual Property

All content, trademarks, and intellectual property related to VaultBytes and our Services remain our exclusive property. You may not copy, modify, or distribute our proprietary materials without permission.

9. Patents

The CipherExplain SHAP explainability method and FHE Differential Testing Oracle are covered by pending patent applications filed under the Patent Cooperation Treaty: PCT/IB2026/053378 (Differential Testing Oracle) and PCT/IB2026/053405 (CipherExplain SHAP). Use of the Services under these Terms does not grant any patent licence, express or implied. For patent licensing enquiries, contact b@vaultbytes.com.

10. Disclaimer of Warranties

THE SERVICES ARE PROVIDED "AS IS" WITHOUT WARRANTIES OF ANY KIND, EXPRESS OR IMPLIED. WE DO NOT WARRANT THAT THE SERVICES WILL BE UNINTERRUPTED, ERROR-FREE, OR COMPLETELY SECURE. THE CIPHEREXPLAIN API IS NOT A SUBSTITUTE FOR PROFESSIONAL LEGAL, REGULATORY, OR COMPLIANCE ADVICE.

11. Limitation of Liability

TO THE MAXIMUM EXTENT PERMITTED BY LAW, VAULTBYTES SHALL NOT BE LIABLE FOR ANY INDIRECT, INCIDENTAL, SPECIAL, CONSEQUENTIAL, OR PUNITIVE DAMAGES ARISING FROM YOUR USE OF THE SERVICES. OUR TOTAL AGGREGATE LIABILITY SHALL NOT EXCEED THE FEES PAID BY YOU IN THE THREE MONTHS PRECEDING THE CLAIM.

12. Indemnification

You agree to indemnify and hold harmless VaultBytes from any claims, damages, or expenses (including reasonable legal fees) arising from your use of the Services, your model data, or your violation of these Terms.

13. Termination

We may suspend or terminate your API key and access to the Services at any time for violation of these Terms, non-payment, or abuse. Upon termination, your registered models will be deleted within 30 days. Provisions that by their nature should survive termination (including sections 8, 9, 10, 11, 12) shall survive.

14. Changes to Terms

We may modify these Terms at any time. We will notify paid-tier customers by email at least 14 days before material changes take effect. Continued use of the Services after changes constitutes acceptance of the modified Terms.

15. Governing Law

These Terms are governed by the laws of England and Wales. Any disputes arising out of or in connection with these Terms shall be subject to the exclusive jurisdiction of the courts of England and Wales.

16. Contact

For questions about these Terms, contact us at:

b@vaultbytes.com