Kryptos is an encrypted sculpture by Jim Sanborn at CIA headquarters in Langley, Virginia, installed in 1990 as both public art and a cryptographic challenge shaped by themes of secrecy and intelligence gathering. Its central copper screen contains four encrypted passages created with help from retiring CIA employee Edward Scheidt, mostly using variants of the Vigenère cipher. Three passages have been solved, but the fourth, known as K4, remains unsolved despite decades of effort by amateur and professional cryptanalysts. With its surrounding landscape elements and lingering irregularities, the work became a landmark puzzle and an enduring mystery at the symbolic heart of American intelligence.

Photo: Wikipedia · Public domain

Photo: Wikipedia · Public domain

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