"They want to modernize but the cost of this effort is information, which could easily destabilize the regime," said Victor Cha, former director for Asian affairs at the National Security Council in the George W. Bush administration, and now a professor at Georgetown University. "Without control of information, there is no regime."
Exactly when the latest crackdown began isn't clear. Many analysts date it to early 2011, as Pyongyang watched the wave of protests sweeping the Arab world. But it also appears to have intensified since the December 2011 death of North Korea's longtime leader, Kim Jong Il, and the rise of his son, Kim Jong Un. The younger Kim, almost completely unknown until late 2010, is believed to be about 29 years old.
In the clearest sign of the crackdown, the number of North Korean refugees reaching South Korea in 2012 has dropped by almost half, to about 1,400, compared to last year. While that statistic doesn't include every North Korean who fled across the border, many of whom spend years living underground in China, it is widely seen as a general indication of the increased frontier security.
But the North Korean market for outside knowledge, nearly all observers say, has become insatiable. It's been more than a decade since everyday North Koreans caught their first real glimpses of the outside world, when a breakdown in government control during the 1990s famine combined with the arrival of cheap Chinese electronics. The hunger for the larger world resembles, in many ways, the appetites in China in the years after Mao Zedong's 1976 death, when Beijing began opening the door for the world's mass media.
Today in North Korea, the idea of winning a fight against information seems an impossible goal.
If nothing else, said a onetime smuggler who eventually fled to South Korea, too many powerful North Koreans are making money in the business. He clearly remembers his early televised revelations, when DVDs showed him so much that his own country didn't have.
"I felt sad about the state of my country when I watched the DVDs," said the defector, who now lives in Seoul and spoke on condition he not be named, fearing retribution against family still living in North Korea. "I could see Hong Kong, Taiwan, South Korea, the United States ... these other places were so much better off."
Associated Press writers Sam Kim and Hyung-jin Kim contributed from Seoul.
Follow Tim Sullivan on Twitter at twitter.com/SullivanTimAP.