(CNN) -- The creator of the enigmatic "Kryptos" sculpture at the CIA's headquarters is dangling a substantial clue before code-breakers eager to unravel the work's hidden messages.
"Kryptos" -- which means "hidden" in Greek -- is a copper wave composed of four panels stamped with seemingly random letters that in fact contain distinct coded messages.
The first three codes were cracked in 1998, eight years after the sculpture was erected at the CIA's then-new headquarters in Langley, Virginia.
According to Jim Sanborn, the artist, the fourth and final code is the hardest to crack. His recent revelation that six of the 97 letters in this section spell "Berlin" is sending shock waves through communities of fans and code-breakers.
"Well, there were several reasons (for releasing the clue)," Sanborn told CNN. "One is that November 6th, 20 years ago was the dedication of 'Kryptos' at the CIA headquarters.
"And it's also my birthday month, and so I figured, I've got to do something for the anniversary, that's the reason for the timing."
The other reason, he said, was that he was "getting tired of the continued and somewhat escalating number of people contacting me and saying that they had cracked the code."
It was for this reason that he set up the website, Kryptosclue.com. Would-be code-breakers now have an official means of logging what they think the message is with Sanborn.
Though he meant for the code to be tough to work out, Sanborn is surprised it has taken people so long to crack it.
"Well, the first three sections I figured would be decoded in a matter of weeks; they took several years," he said. "I'm not quite sure why, but it took a very long time."
Still, Sanborn is keen to point out that those not gifted with mathematical skills are as much capable of cracking the code as those with advanced numerical minds.
"I'm what I call an anathemath," he said. "As an artist you can come up with myriad coding systems."
Former CIA agent and cryptographer Ed Sheidt, who helped Sanborn encrypt the codes contained in the work, agreed that mathematics isn't the only way to crack a code.
"The interesting thing is I tried to minimize that," he told CNN. "If someone had math, then OK, that's an avenue for that person. But sometimes -- this sounds bad -- you can know too much and miss it."
Sheidt, who described himself to CNN as "on the side of the puzzle," explained that linguistics, too, plays a part in cryptography.
"Kryptos" has spawned numerous websites over the years, accruing thousands of fans -- and some obsessives.
"There is obsession," Sanborn said. "I mean, I get hundreds of pages from people who are completely obsessed with this."
Many, he said, are conspiracy theorists that have delusions about the messages contained in the sculpture. "But that's not code-breaking," he said.
It's not just puzzle-lovers and conspiracy theorists who are captivated by "Kryptos." The author of "The Da Vinci Code," Dan Brown, incorporated the work into the plot of his sequel "The Lost Symbol," a fact that Sanborn is not too happy about.
"I think all art work is open to interpretation but (it) should be in some way sacrosanct, in that each artist should come up with their own ideas and not necessarily appropriate other people's work," he said.
Even with the clue being given out, it is possible that the final message contained in "Kryptos" may not be decoded in Sanborn's lifetime. He has made provisions for this, however.
"I think it would be great if it retains its mystery, I will probably give out some other clues in 10 more years, and if I'm still around, 10 more years after that," he said.
"I have two very trusted friends, younger than myself, who know how to get to where the answer is," he continued.
"It's not easy, but in the event of my demise, it could be found out," he said.