CIA Agent David Stein’s Internal Report details the methods used to decrypt the first three of several encryptions on James Sanborn’s Kryptos Sculpture. The original document released internally to the CIA has been reproduced on the kryptos.info network, and an exclusive reconstruction has been been made available for download as a pdf.
Original details of this document can be found at Elonka Dunin’s Mirror Archive.
Kryptos Info 