Kryptos is the name of a sculpture at the headquarters of the Central Intelligence Agency that was dedicated in October 1990. The sculpture, which has 865 characters, was placed there as a whimsical challenge but has stumped and obsessed cryptographers around the world for nearly a decade.

Jim Sanborn, the artist who designed Kryptos, said he believes that the ultimate secret hidden in the text of Kryptos will never be deciphered. The actual cryptogram was designed by Edward M. Scheidt, a former chairman of the C.I.A.'s Cryptographic Center. Ed Scheidt, the retiring chairman of its Cryptographic Center, was hailed by then-director William Webster as "The Wizard of Codes." Scheidt figured that the first chunks of the puzzle would stand a few years; the last part, perhaps ten. He didn't know his own strength.

So far only a small handful of people have been able to decipher portions of the code. The fourth and final piece has been attempted by both the C.I.A. and the National Security Agency with no luck. To this day it remains unsolved. Do you think you have what it takes to decipher the world's hardest cryptogram?

The Solution:

Three parts of Kryptos have been decrypted so far. Note: The word "iqlusion" in part one is not a transcription mistake. This is how it is actually encoded in Kryptos.

* Between subtle shading and the absence of light lies the nuance of iqlusion.

* It was totally invisible.How's that possible? They used the earth's magnetic field. x The information was gathered and transmitted undergruund to an unknown location. x Does Langley know about this? They should: it's buried out there somewhere. x Who knows the exact location? Only WW. This was his last message. x Thirty-eight degrees fifty-seven minutes six point five seconds north, seventy-seven degrees eight minutes forty-four seconds west. ID by rows.

* Slowly, desparatly slowly, the remains of passage debris that encumbered the lower part of the doorway was removed.
With trembling hands I made a tiny breach in the upper left-hand corner. And then, widening the hole a little, I inserted the candle and peered in. The hot air escaping from the chamber caused the flame to flicker, but presently details of the room within emerged from the mist. x Can you see anything?