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Fingerprint drift
Almost everything written about fingerprinting is about not being detectable — whether your canvas hash is unique, whether your GPU string looks real. That is the wrong half to worry about once an account exists. A site that has seen your account sign in has already stored what that device looked like, and the loudest thing you can do afterwards is show up as a different one. Not an unusual computer. A changed one.
Why a change is louder than an oddity
An unusual fingerprint puts you in a small bucket. A changed fingerprint on an existing session puts you in a specific, well-understood bucket that every consumer platform already has machinery for: this account is being accessed from hardware it has never used before. That machinery predates fingerprinting and exists for a good reason — it is the same check that catches a stolen password.
So the outcomes are the ones you would expect from a security system rather than an anti-bot one: a verification email, an SMS challenge, a request to confirm a device, a session dropped back to the login screen, or a hold on the account while someone looks at it. If you have ever had a profile that worked for weeks and then suddenly needed to re-verify, a device change is the first thing worth ruling out.
Real devices change too — but only in certain ways
The goal is not a fingerprint frozen in amber. A real computer's fingerprint moves constantly, and one that never moves at all is its own anomaly. What separates an ordinary change from a suspicious one is which parts moved, and how fast.
| Change | How a real device behaves |
|---|---|
| Chrome version | Goes up every few weeks, forever. A version that never moves is the odd case. |
| Screen resolution | Changes when a monitor is plugged in, and changes back. Rarely, and not at random. |
| Timezone | Changes when you travel — together with the IP, not separately from it. |
| Language | Almost never. People do not switch their OS language. |
| GPU / CPU cores / memory | Effectively never. Hardware does not change under a running account. |
| Canvas / audio / WebGL hashes | Shift slightly with driver and browser updates; do not jump to an unrelated value. |
Read that table as a list of what you can safely let move. A browser version that climbs is invisible. A graphics card that changes overnight, on an account that was signed in yesterday, is not — because there is no story for it. People do not swap GPUs between sessions.
What reissues an identity without looking like it
A profile's fingerprint is not stored field by field. It is derived — expanded from one stable seed into an operating system, a screen, a GPU, a locale and the noise that shapes canvas and audio readings. That design is what makes a profile the same machine every morning. It also means anything that changes an input to that expansion changes the output, including settings that do not look like they touch the fingerprint at all:
- Regenerating the fingerprint. The obvious one, and the only one that announces itself.
- Switching the operating system the profile claims. The screen sizes, GPU strings and platform values all come from the OS, so changing it necessarily changes them.
- Pinning or unpinning the browser version. The user-agent and the client hints are derived from it, and they are among the first things any site reads.
- Setting a resolution or language override after the profile has been in use. Both are legitimate, and both are visible.
The trap in that list is that some of these look like no-ops. Opening a profile's settings and selecting the operating system it already reports feels like confirming a value, not changing one.
Measured: the no-op that was not one
We found this in our own generator, so it is worth being specific about rather than abstract. Every value in a Parallel fingerprint is drawn in sequence from the profile's seed. Choosing the operating system by hand skipped one draw in that sequence, which shifted every value after it.
Across 200 profiles, pinning each one to the operating system its seed had already chosen produced a different machine every single time:
OS on Auto Windows 1920x1080 Intel UHD Graphics
OS pinned Windows 1536x864 AMD Radeon RX 6600Same profile, same operating system, different screen and a different graphics card. Nothing in the interface suggested anything had happened. Any site that had seen that profile before would have seen a new computer on the next launch.
This is fixed in v0.0.66: the draw happens either way and is discarded when an OS is pinned, so pinning the value a seed would have chosen anyway is now genuinely nothing. Profiles left on Auto were never affected and are byte-for-byte unchanged — we checked 300 of them against the previous version before shipping it.
We are writing it up because the general lesson outlives our bug: in any tool where the fingerprint is derived rather than stored, a setting that looks cosmetic can reissue the whole identity. If a change of setting is followed by an unexpected re-verification, that is worth treating as cause and effect rather than coincidence.
Keeping a profile stable
- Decide the OS, version pinning and overrides before the profile signs into anything. All of them are free to change on day zero and expensive to change on day ninety.
- Let the browser version climb. It is the one part of the fingerprint that is supposed to move, and pinning it forever eventually becomes the anomaly.
- Change one thing at a time, and not while signed in. If a profile must change, give the site an ordinary session afterwards rather than a burst of activity.
- Check before and after. Open the fingerprint check in the profile, note what it reports, and compare after any settings change. It takes a few seconds and it is the only way to know whether a change you made was visible.
- Keep the seed. Moving a profile between machines should carry its seed, not generate a new one — see profiles for what an export actually contains.
Related
- How accounts get linked — the signals that tie two profiles together, rather than the ones that change within one.
- Browser fingerprinting explained — what the individual signals are, and which ones actually carry weight.
- Why you keep getting logged out — the other common cause of a session that will not hold.
A profile that stays the same computer
Parallel derives each profile from one stable seed, so its screen, GPU, locale and canvas noise are the same every morning — and settings that should change nothing now change nothing. Three profiles free, forever.
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