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Canvas fingerprinting test
Canvas fingerprinting reads how this device paints text and shapes. The hash stays in this tab. A stable hash is not proof that the value identifies only you.
- Drawn in this tab
- No image upload
- Second draw checks stability
- No global uniqueness claim
Canvas fingerprinting test?
Canvas fingerprinting reads how this device paints text and shapes. The hash stays in this tab. A stable hash is not proof that the value identifies only you. Nothing is read until you start the scan. This page load does not draw a canvas, open WebRTC, or ask the server for an address.
RFC 8828: WebRTC IP Address Handling Requirements
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Scan browser
Nothing is read until you start the scan. This page load does not draw a canvas, open WebRTC, or ask the server for an address.
What it tests
The page paints text, a circle, a gradient, and a composite operation, then reads the pixels.
A second identical drawing shows whether the result stayed put or moved.
Why it matters
Sites use canvas readback because the pixels can vary by GPU, driver, OS, and fonts, without setting a cookie.
A blank or blocked readback means this browser did not hand over a usable image.
How the test works
The hash is SHA-256 of the full RGBA pixel buffer plus a fixed drawing version. Two matching hashes mean the drawing was stable this time.
If the read throws, the row is browser-blocked.
What the result means
Fingerprinting risk is based on the stability and combination of signals, not proof that this individual canvas hash uniquely identifies you.
A changed hash can mean noise or randomization. That reduces cross-visit linking. It can still be linkable inside one session.
How to reduce exposure
Browsers that block canvas readback, add noise, or return a standard image will change this result.
Switching browser or privacy mode is the practical test. Use Scan again after you change it.
Questions
Is a stable hash unique?
No. Many machines can share a result, and one machine can change after an update.
Do you upload the canvas?
No. The pixels and the hash stay in the page.