Almost 20 years after its dedication, the text has yet to be fully deciphered. A bleary-eyed global community of self-styled cryptanalysts—along with some of the agency’s own staffers—has seen three of its four sections solved, revealing evocative prose that only makes the puzzle more confusing. Still uncracked are the 97 characters of the fourth part (known as K4 in Kryptos-speak). And the longer the deadlock continues, the crazier people get.

[…]

The 97 characters of K4 remain impenetrable. They have become, as one would-be cracker calls it, the Everest of codes. Both Scheidt and Sanborn confirm that they intended the final segment to be the biggest challenge. There are endless theories about how to solve it. Is access to the sculpture required? Is the Morse code a clue? Every aspect of the project has come under electron-microscopic scrutiny, as thousands of people—hardcore cryptographers and amateur code breakers alike—have taken a whack at it. Some have gone off the deep end: A Michigan man abandoned his computer-software business to do construction so he’d have more time to work on it. Thirteen hundred members of a fanatical Yahoo group try to move the ball forward with everything from complex math to astrology. One typical Kryptos maniac is Randy Thompson, a 43-year-old physicist who has devoted three years to the problem. “I think I’m onto the solution,” he says. “It could happen tomorrow, or it could take the rest of my life.” Meanwhile, some of the seekers are getting tired. “I just want to see it solved,” says Elonka Dunin, a 50-year-old St. Louis game developer who runs a clearinghouse site for Kryptos information and gossip. “I want it off my plate.”

via Mission Impossible: The Code Even the CIA Can’t Crack.

Pfft. I bet the NSA could crack it in seconds. 😛