In short
- Most trials are reset by reinstalling, deleting a file, changing the clock or signing up again.
- A good trial is the full app, once per person, ending on time even offline.
- Pramaan remembers each trial by the device's key, a private hash of the buyer's account and a phone's install ID, for good.
- Expiry runs on the security chip's clock, and buying swaps the trial for a full licence in place.
How trials get reset
- Reinstalling, when the trial lives in a file or the registry.
- Changing the clock, when expiry trusts the system clock (clock tampering).
- A new account or email, when the trial is tied to a sign-up.
- A new device ID, when the hardware fingerprint is easy to change.
Once per person, remembered for good
Pramaan's storefront keeps a trial ledger for each app and checks every identity a request gives: the device's key in its security chip (which reinstalling doesn't change), a hash of the buyer's Pramaan account that only that publisher sees (so a new computer doesn't help), and on phones an install ID that survives reinstalling the app. The ledger is kept with the app for good, through new versions and redeployments.
Ending on time, offline
The trial licence carries its end date and the guard judges it against the TPM's own clock, which can't be set back, so the trial ends on time on a machine that never goes online. A computer part-way through its trial can update to a newer release for the days it has left.
Turning a trial into a sale
When the trial ends, the app shows its Buy button. The buyer pays (in USDC, USDT, ETH or BTC) and the storefront issues a full licence for the same computer, swapped in over the trial copy with nothing to reinstall. Set it up in the listing editor: 7, 14 or 30 days. See selling on Pramaan Marketplace.
Questions
How do I stop users resetting a free trial?
Tie the trial to things they can't easily change and remember it for good. Pramaan records each trial by the device's security-chip key, the buyer's account and a phone's install ID, so reinstalling, a new account or a new install doesn't start another.
Can a trial expire on an offline computer?
Yes. The end date is in the licence and judged against the TPM's clock, which can't be rewound.
Does buying after the trial need a reinstall?
No. The full licence replaces the trial licence on the same computer.
Related guides
- Perpetual vs Subscription Licenses and TrialsSoftware licensing models compared: perpetual licences, subscriptions, free trials, and which suits offline, desktop and enterprise software.
- How to Sell Software Online and Get Paid InstantlySell desktop and phone apps online: free trials, offline licences, instant stablecoin payouts, licence resale with royalties, and no licence server to run.
- How to License a Python, Electron or .NET AppAdd licensing and copy protection to a desktop app in any language: encrypt the valuable part and check the licence offline through a small C library.
See it working: follow the pictures, browse Pramaan Marketplace, or start free.