WASHINGTON -- Imagine a burglar with the key to your house and the code to turn off your alarm system, making it easy to steal from you without you knowing anything happened.
That could be happening on your computer right now.
Experts warn that unseen cyber-thieves use aptly named "spyware" programs to snoop around computers, farming personal data and passwords and tracing every keystroke users make.
Some members of Congress are trying to beef up laws against cyber-snooping, but critics say the proposals might go too far.
Few disagree about spyware's potential for damage.
"There is a huge continuum of harm that can be caused, from a nuisance and annoyance to major identity theft issues," said Rick Quaresima of the Federal Trade Commission. "That's the real danger."
Unwanted spyware programs furtively monitor and record personal behavior on the Internet, and they can clog a computer's arteries, grinding its processing speed to a plodding pace.
Spyware can get into a computer in many ways, often secretly downloading when users are installing other software online.
Spyware itself is not illegal, but it often is used for illegal purposes. The Justice Department and the FTC have the authority to pursue spyware purveyors. At least 10 states, mostly in the West, have anti-spyware laws on the books.
The House of Representatives recently passed two bills to further discourage spying.
The so-called Spy Act, which received an overwhelming 368-48 vote of approval last week, has gained more attention for its broader focus. Primarily, it would arm consumers with additional tools to ward off spyware.
The bill requires:
A user to consent before receiving downloaded spyware.
Making all spyware programs easy to delete.
Stiffer fines of up to $3 million for anyone violating parts of the act; the current maximum fine is $11,000 for each spyware-related offense.
"People have no idea that someone can access their keystrokes," said Rep. John Shimkus, an Illinois Republican and member of the House committee that handled the Spy Act. "They're going to say, 'I don't want that to happen.'"
"Being able to clearly identify what's getting downloaded and having it where the consumer can disable it is critically important," he added.
Critics, including many Internet companies and online advertisers, objected over concerns that the bill is too broad, especially in a field with new technologies constantly cropping up.
Critics also worry that Internet features such as "cookies" will be adversely affected, despite exemptions in the bill. Cookies are online nametags stored on computers to help Web sites remember the users and their information when they visit. They can also help advertisers target their messages.
Republican Rep. Roy Blunt of Missouri voted against the Spy Act, saying that the bill over-regulates the issues.
He prefers a separate bill with a narrower, judicial focus that passed the House last month. That bill, named the I-SPY Act, creates spyware-related criminal offenses.
The legislation also raises maximum prison sentences to five years for the spyware-based charges and gives an extra $10 million a year to the Justice Department to prosecute spyware abusers "without threatening legitimate businesses," said Blunt spokeswoman Burson Snyder.
Spyware can bombard people with pesky pop-up ads while they surf the Web. It can cause computers to crash.
But hackers, for whom spyware is a key tool, can do far greater damage.
Just ask Jessica Robinson, press secretary for Missouri Gov. Matt Blunt. In late 2004, a cyber-thief extracted financial records and private nude photographs of her from Robinson's home computer - images that surfaced again in March. Robinson's husband had taken the photos to chronicle her pregnancy.
Although anti-spyware bills in recent years have gone nowhere in the Senate, Shimkus said he thinks that pattern will change.
"We're on the side of the angels on this one," Shimkus said, "because in this world and age, privacy is a major concern to the vast majority of Americans."