In the courtyard between CIA’s Original Headquarters Building (OHB) and the New Headquarters Building (NHB) stands a copperplate screen with letters cut into it. This screen is the centerpiece of Kryptos, a sculpture that also contains an enciphered message. The artist—Washington DC native James Sanborn—used several methods of cryptography in creating Kryptos and its hidden message. The artwork’s other components include granite sections flanking the walkway outside the NHB entrance, a pool and additional granite slabs in the courtyard, and the petrified wood supporting the screen. To date, cryptanalysts have cracked three sections of the coded message, but a solution to the fourth section remains elusive.