For those who cheat on their spouses, the Web has taken promiscuity into the digital realm. E-mail flirting, Instant Message sex, photo and video files: All these digitized expressions of passion can sometimes lead to trysts in the real world.

But thanks to a new kind of software designed to record the keystrokes, e-mail, passwords, and Web surfing habits of a computer user, private eyes, too, have received a digital overhaul.

The power, popularity, and potential for misuse of such programs has law enforcement agencies and lawmakers scrambling to ensure they won't be abused.

'Are you concerned about what your spouse, employees or children do on the Internet while you're away?' — eBlaster

As a Michigan man who installed a program called eBlaster on his estranged wife's computer recently learned, using the software the wrong way can land you in jail.

Steven Paul Brown, 41, was charged this week with four felony counts of using a computer to eavesdrop for installing the software on Patricia Brown's computer. If convicted, Brown could face up to five years in prison and $19,000 in fines.

Brown blew his cover when he asked his wife's friend about information the two women had discussed privately over e-mail. Patricia Brown filed a complaint with the high-tech crime unit of the Michigan attorney general's office, and investigators, who knew what to look for — thanks to the cooperation of the software's manufacturer, SpectorSoft — quickly found the hidden bug on her own computer.

The case was one of three brought by Michigan Attorney General Jennifer M. Granholm against four defendants in a round up of e-snooping activities.

"These cases show the need for computer owners everywhere to be ever watchful over their computer systems," Granholm said. "Just as you have to be careful that you don't leave your front door wide open when you go on vacation, you can't leave your computer unsecured either."

How the eSpying Software Works

Hidden from view, the computer software programs do anything from logging previous Web sites the user has visited to taking snapshots of the screen at different intervals in time and to recording Instant Messenger conversations to copying e-mails as they are sent out. Some are even tailored to detect and record passwords in a special file.

The programs offer a way around encryption schemes—which can protect data from so-called "packet sniffing" programs that "sniff" for specific bits of data passing through a centrally-located server—by recording data as it is entered.

"It's sort of like a VCR recording your TV, except it's recording your computer," explains SpectorSoft president Doug Fowler.

This means that information the user might think is secure—from credit card numbers to passwords—could be captured despite conventional security methods, Fowler said.

What makes programs like eBlaster dangerous, authorities say, is that they can be set to "stealth mode," surreptitiously spying on the user's activities. They can even send a log of the information collected to an outside email address, allowing invader to monitor computers they don't own or have regular access to, as Brown did.

'It's sort of like a VCR recording your TV, except it's recording your computer' — one e-spying software company executive says

Software companies market their e-spying products to businesses, parents who want to monitor their children as well as adults who want to keep tabs on the online activities of their spouses. "Are you concerned about what your spouse, employees or children do on the Internet while you're away?" reads a message on Spectorsoft's Web site. "You can't always be around to watch over their shoulders, so hire a second pair of eyes with eBlaster."

But Fowler insists the company's products are meant to be used legally.

"We don't support the idea of somebody being able to install this on someone's computer and not tell them," he said. Fowler said the licensing agreement that comes with the eBlaster software requires that the program only be installed on one's own computer, and that each user be informed of the surveillance.

But the installation process does give the user the option to hide the program, making it invisible with only a click.

Who's Spying on Whom?

Recording computer activity is nothing new. According to a study by the Privacy Foundation, a Denver-based advocacy group, one in three employers in the U.S. monitor the computer use of their employees. Many employers use programs like eblaster.

This back-door loophole is so powerful that a similar program was even used by the FBI in 1999 to bring down Nicodemo Scarfo, the son of a former Philadelphia mob boss. Scarfo was suspected of heading a New Jersey loan-sharking operation with mafia ties, but he reportedly used a popular encryption software which prevented the FBI from intercepting his electronic communications.

So the agency obtained a court order to break into Scarfo's house and install a keyboard sniffing device on his computer, which allowed agents to obtain his password and eventually obtain enough information from his computer to indict him.

'We've had people who said their marriages have been saved over this' — one expert says

But while employer and governmental surveillance is protected under acts such as the 1996 Federal Electronic Communications Act, private monitoring is a different matter. And it has rights groups worried.

"I think we're facing a real explosion of new privacy violations," said Jay Stanley, the ACLU's privacy public education coordinator.

Stanley believes that while the Michigan case may demonstrate that the law is equipped to deal with some personal privacy violations, "Overall, the law is in the Stone age. It's way behind technology on this kind of thing."

Fear of the 'Trojan Horse'

At the extreme end of privacy violating programs that have both rights groups and governmental groups worried are software such as Subseven, which can act like a Trojan horse, infiltrating computers when users open seemingly harmless attachments like images or video files.

Originally designed to allow users to control their computers from remote locations, the programs have been adapted by hackers to allow them to invade and control other people's machines.

Fowler feels his program is a far cry from such Trojan Horses. "That is crossing the line as far as we're concerned," he said, noting that his company has been asked to design such software but has declined.

He thinks his software helps most people who use it. "We've had people who said their marriages have been saved over this," he said.

One "success" story came when his software has helped a woman find out her fiancee was using the Internet to set up a rendezvous with several women a day for real-world sex. Another time, it helped a man who suspected his wife of cheating discover not only that she was cheating, but that she and her new boyfriend were plotting to kill him.

And of the relationships his software breaks, Fowler said, "The marriage is pretty much shot at that point anyway, because of lack of trust. At this point they just want to be sure. We don't feel that we cause divorces—we don't cheat on their wives or husbands."