Terms of Service

1. What Sigil Does

Sigil is a media provenance platform. You upload content (currently images, with additional media types planned) and we create a cryptographic signature (a "sigil") that links that content to your identity. Anyone can later verify whether content carries a sigil and who signed it.

We do not distribute or license your uploaded content to third parties. However, the fact that content has been signed, the identity of the signer, and the signing timestamp are publicly verifiable by design.

2. Accounts and Subscriptions

You must provide accurate information when creating an account. You are responsible for keeping your account credentials and signing keys secure. If you believe your account or keys have been compromised, notify us immediately.

Sigil is a paid service. By subscribing, you agree to pay the fees associated with your chosen plan. Fees are billed in advance on a monthly or annual basis. All fees are non-refundable except as required by applicable law.

We may change our pricing with 30 days' notice. Price changes take effect at the start of your next billing cycle. If you do not agree to a price change, you may cancel your subscription before the new price takes effect.

We may offer different service tiers with varying features, volume limits, and support levels. The features available to you depend on your subscription plan.

If your subscription expires or is cancelled, your existing sigils remain valid and publicly verifiable. You will retain read-only access to your signing history. However, you will not be able to sign new content until you resubscribe. We may delete stored copies of your uploaded content after a reasonable retention period, but your sigils and cryptographic signatures will remain in the system permanently.

3. Signing Keys

Your account may be issued one or more Ed25519 signing keys. These keys are used to cryptographically sign content and are tied to your identity. You are responsible for the security of your private keys.

If a signing key is compromised, we will revoke it upon your request. Sigils created with a revoked key remain in the system but are flagged as created with a revoked key.

4. Ownership: The Core Rule

By signing content through Sigil, you represent and warrant that you created the content yourself, or that the rights holder authorized you to sign it.

This is the core obligation of using Sigil. A sigil is a public assertion of origin. Signing content you did not create and do not have rights to is a breach of these Terms and may expose you to legal liability.

5. Duplicate Detection

When you submit content for signing, our system checks whether substantially similar content has already been signed. If a match is found, the signing request will be rejected.

Duplicate detection is not infallible. A passed check means no existing match was found in our system, not that we have verified your rights to the content. You remain solely responsible for ensuring you have the right to sign any content you submit.

6. Disputes and Challenges

If you believe someone has signed content that belongs to you, contact us at legal@sigilproof.com with evidence of your ownership (raw files, metadata, publishing history, contracts, or other documentation).

Where a dispute involves a claim of copyright infringement, the DMCA process described in Section 9 applies. This section covers ownership disputes that fall outside the DMCA.

We will review disputes at our discretion. We may request cooperation and evidence from both parties. We reserve the right to void, suspend, or leave unchanged any sigil based on the evidence presented.

We are not a court, arbitrator, or mediator. Our dispute review is a good-faith effort, not a legal determination of ownership. You retain the right to pursue legal remedies independently.

7. Prohibited Conduct and Enforcement

You agree not to:

• Sign content you do not own or have authorization to sign.
• Use the Service to harass, defame, or infringe on the rights of others.
• Upload content that is illegal, contains malware, or depicts child sexual abuse material.
• Attempt to circumvent technical limitations, security measures, or access controls.
• Use automated tools to bulk-sign content without authorization.

We reserve the right to suspend or terminate accounts, void sigils, and take other enforcement action in response to violations of these Terms. Enforcement decisions are at our sole discretion. If we terminate your account for violation of these Terms, you are not entitled to a refund of any prepaid fees.

8. Fraudulent Signing

If you sign content you do not have rights to, you agree to pay liquidated damages of $500 per sigil. This amount reflects the parties' reasonable estimate of the harm caused by false ownership claims, including damage to the true creator, erosion of platform trust, investigation and remediation costs, and the difficulty of calculating actual damages. This provision applies to willful misconduct or reckless disregard for ownership rights, but does not apply to good-faith disputes where you had a reasonable basis to believe you held the necessary rights. Liquidated damages are due upon demand and survive termination of your account.

9. Copyright Infringement (DMCA)

We respect intellectual property rights. If you believe content on Sigil infringes your copyright, send a written notice to our designated agent at legal@sigilproof.com containing:

1. Identification of the copyrighted work you claim is infringed.
2. Identification of the content on Sigil that you claim is infringing, with enough detail for us to locate it.
3. Your contact information (name, address, phone number, email).
4. A statement that you have a good faith belief that use of the material is not authorized by the copyright owner, its agent, or the law.
5. A statement, under penalty of perjury, that the information in your notice is accurate and that you are the copyright owner or authorized to act on their behalf.
6. Your physical or electronic signature.

Upon receiving a valid DMCA notice, we will review the claim and may void the disputed sigil and remove the associated content. We will notify the account holder who signed the content and provide them an opportunity to submit a counter-notification.

A counter-notification must contain: (1) your physical or electronic signature; (2) identification of the content that was removed or disabled and the location where it appeared; (3) a statement under penalty of perjury that you have a good faith belief that the content was removed by mistake or misidentification; and (4) your name, address, and phone number, and a statement consenting to jurisdiction of the federal court in your district (or the District of Delaware, if outside the US) and agreeing to accept service of process from the complaining party. Upon receiving a valid counter-notification, we will forward it to the original complainant and may restore the voided sigil after 10 business days unless the complainant notifies us they have filed a court action.

10. Indemnification

If your use of Sigil causes someone to bring a legal claim against us, you agree to indemnify, defend, and hold us harmless from all costs, damages, and legal fees. This applies when the claim results from:

• Your fraudulent or unauthorized signing of content.
• Your breach of these Terms.
• Your violation of any third party's intellectual property or other rights.

11. Right to Void Sigils

We reserve the right to void any sigil upon determination that the signer lacked rights to the content, violated these Terms, or as required by law. Before voiding a sigil, we will make reasonable efforts to notify the signer and provide an opportunity to respond, except where immediate action is necessary to comply with law or prevent ongoing harm. Voided sigils remain in the permanent record, marked as voided with the reason. They do not disappear. They form part of the audit trail.

12. Cooperation

You agree to cooperate with investigations into potential violations of these Terms, including providing evidence of ownership when reasonably requested. You must respond to cooperation requests within 14 days. Failure to cooperate or respond within the specified timeframe may result in your sigil being voided or your account being suspended.

13. Data, Privacy, and Your Account

Our collection and use of personal information is governed by our Privacy Policy, which is incorporated into these Terms by reference.

We store your uploaded content, cryptographic signatures, perceptual fingerprints, and metadata necessary to operate the verification system. We do not sell personal user data.

Aggregate, anonymized usage data (such as verification volume and trends) may be used for research, reporting, or business purposes.

You may request deletion of your account by contacting us. Upon deletion, we will remove your personal information. However, sigils you created will remain in the system. This is necessary for the integrity of the provenance chain. You may request an export of your signing history before deleting your account.

14. Age Requirement

You must be at least 18 years old to create an account or use Sigil. By using Sigil, you represent that you are at least 18 years of age.

15. Service Availability and Warranty Disclaimer

We provide Sigil on an "as-is" and "as-available" basis. We make no guarantees of uptime, accuracy, or availability. We may modify, suspend, or discontinue the Service or any feature at any time with reasonable notice. We will not be liable for any modification, suspension, or discontinuation.

To the maximum extent permitted by applicable law, we disclaim all warranties, express or implied, including but not limited to implied warranties of merchantability, fitness for a particular purpose, and non-infringement. We do not warrant that a sigil will be sufficient to establish or defend your rights in any legal proceeding.

16. Limitation of Liability

To the maximum extent permitted by law, Sigil Proof PBC is not responsible for any indirect, incidental, special, consequential, or punitive damages, including lost profits, lost data, or missed business opportunities, resulting from your use of Sigil.

Our total liability for any claim arising from these Terms or your use of the Service shall not exceed the amount you paid us in the 12 months preceding the claim, or $100, whichever is less.

17. Governing Law and Dispute Resolution

These Terms are governed by the laws of the State of Delaware, without regard to conflict of law principles.

Any dispute arising from these Terms or your use of the Service will be resolved by binding arbitration under the rules of the American Arbitration Association, rather than in court, except where prohibited by applicable law. For disputes involving amounts less than $10,000, either party may elect to proceed in small claims court instead of arbitration. You agree to resolve disputes individually and waive any right to participate in a class action or class-wide arbitration, to the extent permitted by applicable law. Either party may seek injunctive relief in the state or federal courts located in Delaware.

18. Changes to These Terms

We may update these Terms from time to time. We will notify you of material changes via email to the address associated with your account at least 30 days before they take effect. Continued use of the Service after changes take effect constitutes acceptance of the updated Terms. If you do not agree to the changes, you may cancel your account before the changes take effect.

19. General

If any part of these Terms is found to be unenforceable, the rest remains in full effect. You may not transfer or assign your account or these Terms without our written consent. We may assign these Terms in connection with a merger, acquisition, or sale of assets. These Terms constitute the entire agreement between you and Sigil Proof PBC regarding your use of the Service.

Neither party will be liable for any delay or failure to perform due to causes beyond its reasonable control, including natural disasters, war, terrorism, pandemics, labor disputes, government actions, or failures of third-party infrastructure providers.

You represent that you are not located in a country subject to US government embargo and are not on any US government restricted party list. You will comply with all applicable export control laws in your use of the Service.

Sections 4, 5, 8, 9, 10, 11, 12, 13, 16, 17, and 19 survive termination or expiration of these Terms.

20. Contact

Questions about these Terms? Contact us at legal@sigilproof.com.