Sculpture With Code Poses Mystery at the CIA : Art: Only the designer and the spy agency’s director have the keys to the secret message. The work stands as a tantalizing challenge to the canniest of spooks.

The new, $250,000 sculpture in the inner courtyard at CIA headquarters contains a secret, coded message so difficult to unscramble that it is spooking the agency’s smartest spooks.

Sculptor Jim Sanborn wrote the message, but steadfastly refuses to divulge its contents. He says the text is known only to himself and CIA Director William H. Webster, and neither is talking.

Sanborn’s encrypted brain-teaser is etched in 2,000 letters on the curved copper plates of the outdoor sculpture, titled “Kryptos.” The work was erected outside the mirrored windows of the CIA employee cafeteria, offering a tantalizing challenge to the lunchtime crowd inside.

“Everyone wants to know what it says,” Sanborn said. “They’re out there all the time. There are groups of dark-suited people pointing at it and getting down on their knees, trying to figure out what it says. Some take photographs. One guy copied the whole thing down with pencil and paper.”

Months ago, as rumors of the mystery sculpture swept through the corridors of the CIA enclave in suburban Langley, Va., police caught two men climbing ladders outside Sanborn’s Washington studio. They were trying to photograph the inscription through his windows.

Sanborn said that “a friend of a friend” told him recently that frustrated CIA operatives had sent a copy of the coded message to their archrivals at the National Security Agency to be run through the NSA’s ultra-smart Cray supercomputer.

“The last I heard, they hadn’t gotten very far,” Sanborn said. “They might have figured out one-fourth of it.”

The sculptor, a big, bearded 45-year-old in aviator’s sunglasses, talks freely about his other works, which have been exhibited at the Smithsonian’s Hirshhorn Museum and the Corcoran Gallery of Art in Washington.

But when he speaks of “Kryptos” (Greek for hidden ), Sanborn retreats into the cautious, elliptical speech of someone who is trying to hide something.

He said the sculpture’s message deals on several levels with the CIA tradition of secrecy. He hinted that it was a “collaborative project,” perhaps written with the help of a prominent spy novelist, but he would not elaborate.

The inscription includes a Vigenere table, a system of ciphers devised by the 16th-Century French cryptographer Blaise de Vigenere, and a Vigenere-encoded message that Sanborn says an expert could decipher in a few hours.

The rest of the message, contained in the lower-right quadrant, is “a whole different ballgame” of multiple codes, Sanborn said. It was written by a retired CIA cryptographer whom the sculptor refuses to identify.

Sanborn said that he and the cryptographer conducted business at secret locations, never by telephone or in writing.

“He developed something that really stumped them out there,” Sanborn said. “Parts can be deciphered in a matter of weeks or months, but other parts might never be deciphered without the knowledge that Webster has. He has the key to the code, and he can easily figure the whole thing.”

Sanborn knew that he would have to share his secret with someone at the CIA.

“Their business is to gather information,” he said, “and if they don’t know what’s going on in their own back yard, how would anyone believe they’d know what was going on in the rest of the world?”

When the sculpture was dedicated in November, Sanborn handed Webster two sealed envelopes. One contained a translation of the message; the other held the key words required to break the code.

“Mr. Sanborn . . . you have captured much of what this agency is all about,” the CIA director said. “We like to be tested and we enjoy a challenge.”

“I hope you can keep a secret,” the sculptor said as he gave Webster the envelopes.

“Yes, indeed,” Webster replied. “My lips are sealed. So is this.”

In exchange for his clues, the CIA has allowed Sanborn to haul away 6 tons of soggy paper pulp--what’s left of the agency’s discarded secret documents. After the pulp has dried, Sanborn will use the stuff to make future sculptures imprinted with coded messages in English, Russian and Arabic.

Even if someone breaks the CIA sculpture’s code someday, Sanborn said, the message won’t make sense.

“They will be able to read what I wrote, but what I wrote is a mystery itself. There are still things they have to discover once it’s deciphered. There are things in there they will never discover the true meaning of. People will always say, ‘What did he mean by that?’ What I wrote out were clues to a larger mystery.”