ProofChain is built on a minimal-data principle. We do not track you, we do not profile you, and we do not sell your browsing behavior to advertisers. This policy explains exactly what storage mechanisms the ProofChain website uses, why, and how you stay in control.
This Cookie Policy applies to the ProofChain website and service, available at proofchain.us and any subdomains or associated surfaces that link to this policy. It describes the cookies, localStorage entries, and similar client-side storage technologies used when you visit or interact with ProofChain, how we process the data they carry, and the choices available to you.
References to "we", "us", and "ProofChain" mean the operator of the ProofChain service. This policy supplements, and should be read together with, our Privacy Policy and Terms of Service.
ProofChain operates a no-tracking-by-default website. We do not deploy analytics trackers, advertising pixels, fingerprinting scripts, or cross-site tracking identifiers. We do not use cookies to build a profile of you, to follow you across the web, or to target advertisements at you.
This is a deliberate architectural choice. The ProofChain product itself exists to make AI agent activity verifiable and accountable; it would be inconsistent with that mission to surveil our own visitors. Our storage footprint is limited to what is functionally necessary to operate the site and your session.
The following table lists every cookie and storage mechanism used on the ProofChain website. Where a row is marked "None", we deliberately use no such mechanism.
| Type | Purpose | Duration |
|---|---|---|
| Essential session cookie | Core site functionality — maintaining your authenticated session and preventing CSRF on form submissions. | Session / up to 30 days |
| Stripe checkout cookies | Required by Stripe, our payment processor, to complete and secure payment transactions (see §6). | Set by Stripe |
| Analytics cookies | None — ProofChain deploys no first-party or third-party analytics cookies. | — |
| Advertising / tracking cookies | None — ProofChain does not run advertising, remarketing, or cross-site tracking. | — |
| Third-party cookies | None, except as technically required by the Stripe checkout integration (see §6). | — |
In addition to cookies, ProofChain uses the browser localStorage API to remember lightweight, non-sensitive preferences between visits. Specifically, we store a single flag when you dismiss the cookie notice (so we do not re-show it on every page load).
localStorage entries are stored locally in your browser, are not transmitted to us as analytics, are not readable by third parties, and can be cleared at any time through your browser settings or by executing localStorage.clear() in your browser's developer console.
ProofChain does not use third-party advertising cookies. We do not participate in ad exchanges, retargeting networks, or behavioral advertising. No advertising identifier is ever written to your browser by our site, and no advertising partner receives data about your visits from us.
If you reached ProofChain through an advertising campaign on another platform (for example a search engine), that platform's own cookies may exist in your browser as a result of your interaction with that platform — those cookies are controlled by that platform, not by ProofChain, and are governed by that platform's privacy policy.
When you initiate a payment through ProofChain, the transaction is processed by Stripe, our payment processor. Stripe may place cookies necessary to complete, secure, and validate the checkout flow, including fraud-prevention and session-management cookies. These cookies are set and controlled by Stripe and are subject to Stripe's own privacy and cookie policies.
Stripe's cookies are used solely to process your payment. ProofChain does not use Stripe's cookies for advertising, analytics, or any purpose unrelated to completing your transaction. If you do not begin a checkout, Stripe cookies are not set.
You can control and delete cookies and localStorage at any time through your browser settings. Because ProofChain's storage footprint is minimal, blocking or clearing it will not degrade most of the site's functionality — though you may be asked to confirm the cookie notice again, and authenticated sessions will end when session storage is cleared.
You may also use your browser's private / incognito mode, which discards cookies and localStorage when the window closes, or install a content-blocking extension that strips cookies and trackers by default.
Where we process personal data through the storage mechanisms described in this policy, the legal bases under Article 6 of the GDPR are:
Under the EU ePrivacy Directive (2009/136/EC), as implemented in EU member states and the UK (PECR), strictly necessary cookies and storage may be deployed without consent, while non-essential storage requires consent. ProofChain deploys only strictly necessary storage (session management, security, checkout), and therefore does not require a consent-management banner. We will update this policy and deploy a consent mechanism before introducing any non-essential cookie or tracker.
Article 5(1)(f) of the GDPR requires that personal data be "processed in a manner that ensures appropriate security of the personal data, including protection against unauthorised or unlawful processing and against accidental loss, destruction or damage, using appropriate technical or organisational measures."
ProofChain implements this obligation across the full data lifecycle:
The mechanisms described in this policy — minimal storage, no tracking, no third-party advertising cookies — are themselves part of our integrity and confidentiality posture: the less data we hold, the less there is to compromise.
For clarity, ProofChain does not use cookies or similar technologies to collect: browsing history across other websites; precise geolocation; device fingerprints; email addresses or contact details; social media activity; or any inferred interests or demographic attributes. The absence of these mechanisms is a design decision, documented here so you can rely on it.
Session cookies expire when your session ends or within 30 days, whichever comes first. The localStorage preference flag persists until you clear it or it is removed by browser storage-management policies. ProofChain server logs — which may record IP addresses and request metadata for security purposes — are retained for a limited period, access-controlled, and not used for advertising or profiling.
Because ProofChain does not engage in cross-site tracking, we honor the spirit of Do Not Track (DNT) and Global Privacy Control (GPC) signals by default: there is no tracking to disable. Where a browser sends a DNT or GPC signal, no additional action is required on our part because no tracking mechanisms are deployed.
The ProofChain website is operated from the United States but is accessible worldwide. Visitors from the European Economic Area, the United Kingdom, and Switzerland retain the full protections of the GDPR, the UK GDPR, and the Swiss FADP respectively, including the integrity and confidentiality guarantees in §10. Where personal data is transferred across borders, such transfers are governed by Standard Contractual Clauses where applicable, as further described in our Data Processing Addendum.
We may update this Cookie Policy from time to time to reflect changes in our practices, technology, or legal requirements. Material changes will be announced by posting the revised policy on this page, with the effective date updated accordingly. Where a change would introduce a new category of cookie or storage, we will obtain consent before doing so where required by law.
If you have questions about this Cookie Policy, the storage mechanisms we use, or your rights, contact our Data Protection Officer:
Summary. ProofChain uses no tracking cookies, no advertising cookies, and no third-party analytics. We use a single essential session cookie, a localStorage preference flag, and — only when you check out — Stripe's checkout cookies. You can clear or block all of these in your browser settings at any time. This policy is part of our GDPR Article 5(1)(f) integrity and confidentiality commitments.