AuthentAI witness
The local-first way to prove what you and an AI actually said.
witness turns a ChatGPT, Claude or Gemini conversation into a tamper-evident record — signed on your device, never uploaded, and independently verifiable by whoever you send it to.
What a Witness Record Gives You
Every record rests on three guarantees — an honest capture of the conversation, a signature only you could produce, and proof anyone can check without taking your word for it.
Capture
The conversation, exactly as it happened
- User-initiated — nothing is recorded until you start it
- Hash-chained turns, so no message can be altered or removed
- Versioned selector profiles keep capture accurate as sites change
Sign
Signed on your device, with a key you hold
- A per-record ECDSA signature binds the chain to you
- Keys are held locally — never escrowed, never uploaded
- Digest-only signing, even on the hardware tier
Prove
Anyone can check it without trusting you
- A signed export manifest travels with the record
- Verification is free, for everyone, forever
- One verifier for both machine and human evidence
Three Steps, Start to Proof
From opening a chat to handing someone evidence they can check themselves.
Record
Start the record where the conversation happens
Open witness on ChatGPT, Claude or Gemini and press Start Recording. From that moment, every turn is hash-chained and signed on your device.
Export
Take the evidence package with you
Stop recording and witness writes a .zip containing the conversation, its hash chain, the signatures and the certificate. It lands in your downloads — not on a server.
Verify
Let anyone check it independently
Your recipient drops the package into the open verifier at verify.authentai.com. The chain is recomputed, the signatures checked, and the certificate walked back to a trusted authority.
Privacy Is the Architecture, Not the Policy
Most AI chat loggers work by uploading your conversations to their servers. witness inverts that: capture on the page, sign locally, upload nothing.
Content stays local
Your records live in your browser profile. No witness server ever holds your chats.
What actually crosses the wire
Only identity endpoints — an email confirmation, a code, a certificate request, a thumbprint. Never conversation content.
Local, digest-only signing
The signing path only ever sees a SHA-256 digest of your record — not your text.
After you export, it's yours
A Witness Record is a file. Once you share it, distribution is entirely in your hands.
Works Where You Already Work
witness runs on a narrow, explicit allowlist of three sites — not on every page you visit.
- ChatGPT — chatgpt.com
- Claude — claude.ai
- Gemini — gemini.google.com
Make Your First Witness Record
Step one is a Chrome install and takes about a minute. The free tier is the whole product — no account, no hardware, nothing uploaded.