Tally How a screenshot becomes proof anyone can check.
Three steps. Tally checks the card and saves the verdict on NEAR, so you don't have to trust Tally not to change it.
Every card gets its own fingerprint
Your browser turns the picture into a 64-character code. Change one pixel and the whole code changes.
The picture never leaves your device.
From picture to fingerprint
Example
This card's fingerprint
Change a single byte of the file and watch the whole code change.
The proof is recorded on NEAR
Tally writes the fingerprint and the verdict to NEAR: Real, Unclear or Fake. Nobody can delete or rewrite it, Tally included.
A correction is added on top. The earlier verdict stays.
One card's history, oldest first
Example- Fakek3x9q2
- Realk3x9q2-appeal
Checking doesn't depend on trusting Tally
Drop a card on the demo page and the answer comes straight from NEAR.
No account, no wallet, no Tally server in between.
What goes on NEAR, and what never does
On NEAR
- The card's fingerprint
- The verdict
- The time, set by NEAR
- Tally's id for the check
- The NEAR account that holds a verified card
Never
- The picture
- A name or a handle
- A wallet from another chain
The contract refuses anything that isn't a fingerprint.
Explore the technical details
The fingerprint is a SHA-256 hash
It is the SHA-256 hash of the picture's exact bytes, written as 64 lower-case hex characters. Your browser computes it with its own built-in crypto.
Image privacy
The picture is read on your device and never uploaded. Only the fingerprint is sent to NEAR, and a fingerprint can't be turned back into the picture.
Corrections and appeals
A card's record is a list that only grows. A correction is a new entry on top, with its own check id and time. The latest entry is the verdict that stands, and every earlier one stays readable.
The registry contract
One method writes: record, which only Tally's account can call. The reads are free: get, history, cards and attester. It has 7 unit tests.
A link to any record
Every record has its own link: /demo?fp= followed by the fingerprint. A Tally card's QR code can point to it. Open one.