Last year the author Peter Ludlow attended a birthday party in Germany for Daniel Domscheit-Berg, a technology activist, or "hacktivist," and founder of OpenLeaks. Domscheit-Berg had been a spokesperson for WikiLeaks, but after a public break from Julian Assange, struck out on his own.

Professor Ludlow, who teaches philosophy at Northwestern University near Chicago, expected to find "a bunker full of hackers probing Web sites with SQL injections and sifting through State Department cables."

But what he found was more warm and fuzzy: a small vegetable garden and a tree outside Mr. Domscheit-Berg's house wrapped in a wool sweater, hand-knitted by Mr. Domscheit-Berg's wife Anke - "knit hacking," she called it. She had knit-hacked the town, too. Street signs and the barrel of a World War II tank were covered in her soft wool.

"I interpreted these knit-hackings as counteractions to the attempts to define hacktivist as something sinister," Professor Ludlow wrote in The Times.

The word hacker now summons images not just of data theft, but of ruthless, amoral cybercriminals, even acts of war. This is a long way from its meaning in the 1970s and '80s, when "hackers" were brilliant and sometimes mischievous programmers like Linus Torvald, the founder of Linux, Steve Wozniak of Apple and Microsoft's Bill Gates.

"Forty years ago, a hacker was someone who took great joy in knowing everything about computers," Susan P. Crawford, a law professor at Yeshiva University in New York, told The Times. "The word was really used in admiration. Now it is used to describe and condemn both professional cyberattackers and amateurs who are swept together within the broad description of the word."

Some hackers steal information, some steal money. But others are more ideological. A group calling itself Izz ad-Din al-Qassam Cyber Fighters took credit for recent attacks on the Web sites of some of the largest banks in the United States, The Times reported. Their motive: revenge for the now infamous anti-Islam video that caused violence across the Muslim world last year.

The notion that hacking could be an act of war is taken seriously. The United States Department of Defense has plans to expand its cybersecurity forces against attacks from what Defense Secretary Leon Panetta called a potential "cyber-Pearl Harbor," The Times reported.

"An aggressor nation or extremist group," Mr. Panetta said, could use cybertools to "derail passenger trains loaded with lethal chemicals. They could contaminate the water supply in major cities, or shut down the power grid across large parts of the country."

Despite the dangers, some argue that the government's pursuit of hackers is overzealous. When the well-known programmer and Internet activist Aaron Swartz committed suicide in mid-January, his family and friends blamed the pressure of the government's prosecution. Mr. Swartz, 26, was under federal indictment for making public thousands of academic documents. He faced a $1 million fine and up to 35 years in jail.

After Mr. Swartz's death, Nick Bilton wrote in The Times that the government suffered from a "misunderstanding of what a hacker actually is." Mr. Swartz may have been a "hacker," but his goal was free information, not profit, and not war.

"To many people who understand computers and the law, there is a danger in lumping people who have not sought financial gain with armed robbers. Where people should receive slaps on the wrist, they face decades in prison."

Peter Catapano

(China Daily 02/03/2013 page9)