# Proofstamp

> Add proof where it matters.


## Posts

- [Why Would a Nonprofit Publish Proof Nobody Asked For?](https://proofstamp.org/why-would-a-nonprofit-publish-proof-nobody-asked-for/): What if nonprofits voluntarily made their reports independently verifiable? A simple practice could give donors and the public another way to check important records.
- [Legal Records Outlive Software. Their Proof Should Too](https://proofstamp.org/legal-records-outlive-software-their-proof-should-too/): Legal-tech platforms already track files and audit histories. Could selected legal records carry independent time evidence that remains verifiable after leaving the original system?
- [What If Walmart Didn’t Need to Keep the Return Photos?](https://proofstamp.org/what-if-walmart-didnt-need-to-keep-the-return-photos/): Imagine returning a gaming console to Walmart. You bring back the console, controller, power cable and HDMI cable. The associate processes the return. You hand everything over and leave. Nothing unusual happened. But suppose the return becomes a problem later. Maybe a component is missing. Maybe the console is damaged. Maybe someone questions whether the […]
- [Would You Take Four Photos for 90 More Days of Protection?](https://proofstamp.org/would-you-take-four-photos-for-90-more-days-of-protection/): What if a retailer rewarded customers for creating a better record at delivery? A ProofStamp thought experiment using appliance delivery.
- [They Told Me They Would Refund Me](https://proofstamp.org/they-told-me-they-would-refund-me/): They told me they would refund me. Suppose you’ve already made the call. You explained the charge, waited while someone checked your account, and got an answer: the money would be returned. You saved the recording. As far as you were concerned, that was dealt with. Then the next statement arrives. On the second call, […]
- [When Neither Side Should Control the Record](https://proofstamp.org/when-neither-side-should-control-the-record/): Most digital records do not need anything special. An email confirmation is usually enough. So is a shared folder, a company database, or a PDF saved by both sides. The interesting cases start when something goes wrong. Consider a moving company handling valuable household items. Before packing, the crew photographs their condition and prepares a […]
- [Which ProofStamp Should You Use?](https://proofstamp.org/which-proofstamp-should-you-use/): ProofStamp can preserve the fingerprint of a file in several different ways. The basic idea stays the same: Your file → SHA-256 fingerprint → evidence Your original file stays with you. What changes is where the evidence is recorded, how time is established, and how someone can check it later. Today you can choose between […]
- [How to Keep Verifiable Evidence of an AI Conversation](https://proofstamp.org/how-to-keep-verifiable-evidence-of-an-ai-conversation/): AI is becoming part of ordinary professional work. People use ChatGPT, Claude and other AI tools to research questions, analyze documents, investigate problems and prepare advice. Sometimes the conversation itself matters. If an AI interaction influenced an important decision, could you show later what you relied on? And could someone check that the record you […]
- [Your Logs Are Fine. The Process Around Them Is Changing.](https://proofstamp.org/your-logs-are-fine-the-process-around-them-is-changing/): Why AI-assisted infrastructure work may need durable, independently verifiable traces An infrastructure professional recently told me: “In infrastructure we don’t really have a task to prove timestamps on pieces of information. Everyone simply trusts the logs and their contents.” My first reaction was that he was right. Infrastructure teams already have logs, Git, cloud audit […]
- [Before You Leave the Job, ProofStamp the Photo](https://proofstamp.org/before-you-leave-the-job-proofstamp-the-photo/): A contractor once described a simple dispute. He removed a concrete slab. The next morning, a neighbour claimed the work had caused a crack in another slab. Fortunately, the contractor had a photo taken before the job started. The crack was already visible. That photo changed the conversation. The lesson is simple: keep evidence before […]
- [How to Prove a Photo or Document Existed Before a Specific Date](https://proofstamp.org/how-to-prove-a-photo-or-document-existed-before-a-specific-date/): ProofStamp Email Receipt lets you create a SHA-256 fingerprint of a photo or document in your browser and send it to yourself by email without uploading the original file. It provides a simple way to verify later that a file is unchanged, making it useful for property photos, signed documents, and other important records.
- [Adding Verifiable Proof to Semiconductor Assurance](https://proofstamp.org/adding-verifiable-proof-to-semiconductor-assurance/): Two chip-release manifests carry the same product number. Both look authentic. One was approved before manufacturing. The other appeared later. Which one should a buyer trust? Contracts, certificates, portal records and PDFs can describe what a manufacturer approved, tested and delivered. But those records usually remain inside systems the manufacturer controls. If two copies differ […]
- [AI in Legal Work: What to Record and What a ProofStamp Can Prove](https://proofstamp.org/ai-in-legal-work-what-to-record-and-what-a-hash-can-prove/): AI is becoming part of ordinary legal work. A lawyer may use it to research a question, summarize documents, test an argument, organize information, or prepare a first draft. Most AI conversations do not need to be preserved forever. But some do. If AI-assisted work is questioned months later, reconstructing exactly what happened from memory […]
- [What Is a Hash Function? SHA-256 Explained.](https://proofstamp.org/what-is-a-hash-function-sha-256-explained/): Learn what a hash function is and how SHA-256 turns any file, message, photo, or video into a fixed-length digital fingerprint. This guide explains how hashes verify data integrity, why SHA-256 is widely used, where hashes appear in everyday tech, and what a matching hash can and cannot prove.
- [Trust Is the Invisible Infrastructure of Civilization](https://proofstamp.org/trust-is-the-invisible-infrastructure-of-civilization/): Trust begins where certainty ends. We trust that the person we are speaking with is who they claim to be. We trust that a document has not been quietly altered. We trust that a photograph represents something that happened. We trust that a company will deliver, a bank will protect our money, and an institution […]

## Pages

- [Stories](https://proofstamp.org/stories/): Stories When did you wish you had proof? Think about a real moment when you wished you could show what a file, photo, message, form, AI conversation, or other digital record looked like earlier. We’re collecting real stories to understand where better digital evidence actually matters. Familiar moments Does any of this sound familiar? Sometimes […]
- [Learn](https://proofstamp.org/learn/): Learn Understand the proof before you need it. Plain-language guides to fingerprints, timestamps, file integrity and practical digital proof. Start here Two ideas explain most of ProofStamp. Start with the fingerprint itself, then see how it becomes useful as evidence over time. Basics What is a hash function? SHA-256 explained Understand the digital fingerprint behind […]
- [Try Proofstamp](https://proofstamp.org/try-proofstamp/): Try ProofStamp Choose how to ProofStamp a file. Your device creates a SHA-256 hash of the file. Choose how you want to keep or record that hash so it can be checked later. Email ProofStamp via Email Everyday evidence Create a portable ProofStamp and keep it in an email or saved receipt. No account No […]
- [For Business](https://proofstamp.org/for-business/): For businesses and builders Make important records independently verifiable. ProofStamp explores how customers, partners and reviewers could check important records without relying only on the system that holds them. We explain the methods, build prototypes and explore practical uses with people who know the workflow. Discuss a use case Explore the demos → 1 Your […]
- [AI](https://proofstamp.org/ai/): ProofStamp for AI · Experiment paused We’re rethinking how to make AI conversations verifiable. ProofStamp AI is temporarily paused. Practical chat use created too much capture overhead and depended too heavily on whatever conversation history the AI host exposes. Status: temporarily paused View the experiment on GitHub ↗ Try other ProofStamp tools Existing work stays […]
- [Privacy Policy](https://proofstamp.org/privacy-policy/): Effective date: September 8, 2026 Our website is https://proofstamp.org. ProofStamp is designed to minimize the data we receive. Where a ProofStamp tool says that a file is processed locally, the file stays on your device. We do not receive the file simply because you calculate its SHA-256 hash. This policy explains what information may be […]
- [Contact Us](https://proofstamp.org/contact-us/): Contact ProofStamp Where does proof matter in your workflow? Tell us what you need to preserve, who may need to check it later, and where questions or disputes could arise. We are interested in business workflows, integrations, partnerships, product feedback, and practical uses for verifiable digital records. Add proof where it matters. The point that […]
- [Keep the file. Keep the proof.](https://proofstamp.org/): Our mission Important records.Independently verifiable. ProofStamp helps people understand and use independent verification for important digital records. We explain the idea, explore practical uses and build prototypes to show what’s possible. Explore the demos → Your record handover-report.pdf Keep the original file. ProofStamp Independent time evidence A checkpoint tied to the exact file. Example method: […]

## Optional

- [Agent (MCP protocol)](websites-agents.hostinger.com/proofstamp.org/mcp)

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