We’ve all heard of the dark web, although few of us really know much about it. News reports tell us it’s where criminals buy and sell stolen personal information, such as credit card numbers, bank account passwords, even Social Security numbers.

No wonder credit monitoring companies have added “dark web monitoring” to their list of services. This fear of the unknown just might motivate people to pay $10 - $30 a month for identity theft protection.

But what can dark web monitoring really do for you?

Many people are making false assumptions about that, according to a new survey by the Consumer Federation of America (CFA). The survey found that:

36 percent of those who’d seen ads for dark web monitoring incorrectly believed identity theft services can remove their personal information from the dark web. (They can’t.)

37 percent mistakenly believe these services can prevent stolen information sold on the dark web from being used. (They can’t.)

The reality is: No one can erase the data that winds up in this underground cyber-marketplace or prevent it from being sold, exchanged or used.

“People are making assumptions that are natural, but incorrect,” said Susan Grant, CFA’s director of Consumer Protection and Privacy. “Dark web monitoring may be able to alert consumers that their stolen personal information is being offered for sale on the internet, but it can’t put the genie back in the bottle.”

The Consumer Federation of American wants companies that offer these services to do a better job explaining how they work and what they can — and cannot — do.

THE 411 ON DARK WEB MONITORING

The technology to scan the dark web was developed in 2006. The process, called “scraping,” allows a company to monitor hundreds of chat rooms, websites and peer-to-peer networks that deal with stolen personal identity information and download that data for analysis.

But here’s the part credit monitoring companies don’t tell you: Most of the stolen information being sold on the dark web is shielded from scraping software because it’s behind a paywall.

“There's no way a darknet scraper can find that data whatsoever. These services are completely useless, as far as what they do that for consumers,” said cybersecurity consultant Brett Johnson, a former cybercriminal who helped build the first criminal online marketplace.

Wonder if your information is on the dark web?

“It is,” Johnson said. “There's no need for an individual to pay for dark web monitoring to learn that.”