A free, open-source Chrome extension. When you hit Send, your Mac asks for Touch ID. If you confirm, the email ends with a small stamp linking to a receipt anyone can verify. No Touch ID, no stamp.
That a person, on their Mac, physically authorized this exact email with Touch ID, and that the key which signed it lives in a genuine Secure Enclave, certified by Apple. AI can write text and even fake typing rhythm, but it can't put a finger on a sensor. The stamp attests authorization, not who wrote every word.
A small Mac app shows you the exact message and asks for Touch ID. Your Mac's Secure Enclave signs a hash of it; the chip refuses to sign without a live fingerprint. Apple's App Attest vouches that the key was created inside a genuine Secure Enclave by the signed Inkline app, once at enrollment and again on every stamp. Our notary checks all of it, adds its own signature, and issues a receipt.
Not in software. Enrolling requires Apple's App Attest, which certifies that the signing key was generated inside a genuine Secure Enclave by the signed Inkline app, and every stamp carries a fresh per-send attestation the notary verifies before co-signing. Without attestation the notary refuses to enroll a key or co-sign a receipt. Receipts issued before this policy took effect on 17 September 2026 still verify; the verify page notes they were issued before hardware attestation became part of every stamp. What a receipt can't tell you is who wrote the words.
No. The stamp covers the message text, subject, and addresses. Attachments (files, videos, images) are not part of the signed content. A link in the text is covered, but not what the link points to.
No. Type it, dictate it, paste from your notes. The proof is you confirming the send, not the keystrokes.
Cancel the Touch ID prompt or close the window. The email sends normally without a stamp. Mail is never blocked.
Chrome (and other Chromium browsers) on a Mac with Touch ID running macOS 27 or later, with Gmail. macOS 27 is where Apple made App Attest available to Mac apps; earlier versions install but do not stamp. Recipients can be anywhere.
Yes: github.com/Inkline-Verify/ProofOfHuman holds the extension, the Mac helper, the verify page, and the receipt format, MIT licensed. Verification runs in the recipient's browser and never contacts us.
A way for your product to get a person's approval on an exact action before an agent or automation performs it. Your backend sends the action text; the person approves it; you get a receipt anyone can verify, plus a webhook. See the API page.
Two ways. Touch ID on their enrolled Mac, through a small menu-bar app that shows the exact action. Or a passkey on any device, through a page we host: Touch ID, Face ID, Windows Hello, or a security key.
No, and receipts say which was used. Touch ID approvals are signed by a Secure Enclave key that Apple's App Attest certified at enrollment: hardware-attested. Passkey approvals are signed by a WebAuthn credential the device verified, with no hardware attestation of the key. The verify page labels each tier in fixed wording so they can never be confused.
It is in pilot. We create your company by hand, issue your API key, and help you integrate. Email us.
The canonical action text you asked a person to approve (it is shown to them and embedded in the receipt), the person's public key or passkey credential, your company record, and webhook delivery attempts. Never email content.
Recipients can always check a stamp on the verify page — nothing installed, runs in their browser, and typing the address themselves beats trusting any link.