Cryptojacking is secret mining that uses someone else's computer or browser to create cryptocurrency without the owner's consent.
Unlike the study of ciphers, this abuse spends the victim's processor time and electricity for the intruder's private gain.
How it works
The activity may arrive through a compromised site, a hidden script, or an unwanted program that keeps working after the page is closed.
The device grows hot, slow, or noisy while the mined value goes to someone the owner never chose.
Because the goal is theft of computing capacity rather than theft of files, a quiet machine with odd processor use is a useful warning sign.
Defense centers on knowing which programs may run, watching sustained load, and removing the unwanted miner.
Concrete examples
- A laptop fan runs hard while only a browser tab is open, and the tab is secretly mining for an unknown operator.
- A shared classroom computer stays sluggish all afternoon because a hidden miner survived from an earlier browsing session.
- A cloud bill rises after an intruder runs mining software on a virtual machine that the finance team did not request.
Protective measures
- Alert on computers that hold high processor use for a long time without a matching business task you can name.
- Allow browser scripts only where a site truly needs them, and review extensions that can run on every page.
- Remove unapproved mining programs and rotate credentials for any cloud account that showed unexpected compute use.
- Tell staff to report sudden heat, noise, or slowness so a secret miner is not dismissed as ordinary aging hardware.