Mr. Beige said he did not know why the mask was so popular until recently. “We just thought people liked the ‘V for Vendetta’ movie. Then one morning I saw a picture of these protesters wearing the mask in an online news article,” he said. “I quickly showed my sales manager.”

Guy Fawkes is not well known in the United States, except perhaps through the movie. But in Britain, the foiling of his antigovernment plot — he was put to death — is celebrated as a holiday, Nov. 5 or Guy Fawkes Day, and is commemorated with bonfires and fireworks.

Although the Time Warner-owned image of Guy Fawkes appeared in 2006, it did not take on its new life until much later. That occurred after members of an online message board known as 4Chan showed a crudely drawn stick figure known as “Epic Fail Guy” peering into a trash can and reappearing wearing the mask.

Then in 2008, Anonymous embraced it, explained Gabriella Coleman, an assistant professor at New York University’s department of media, culture and communication. “Thousands of members came out from behind their computer and went into the streets to protest the Church of Scientology,” she said. “Anonymous knew if they were going to meet in a visibly public space for the first time, they needed to conceal their identity. They inevitably chose the ‘V for Vendetta’ mask to do this.”

“It had a chilling effect. There were literally thousands of people standing silently in front of the Church of Scientology wearing the same Guy Fawkes mask,” Ms. Coleman said. “The photos and videos that appeared in the news from the protests cemented the mask as the symbol of Anonymous.”

Warner Brothers did not respond to a request for comment on the mask’s newfound popularity as a tool of protesters.

Alan Moore, the author of the graphic novel on which the movie is based, could not be reached for comment, but in a 2008 interview with Entertainment Weekly, he expressed how proud he was of the mask’s role in the protests of the Church of Scientology.

“That pleased me,” he said. “That gave me a warm little glow.”