Kryptos

Kryptos is the world’s most famous cryptographic artwork. Installed at the headquarters of the Central Intelligence Agency (CIA) in 1990, the work bears an encrypted inscription, a part of which is still unsolved. The sculpture comprises four large copper plates with other elements consisting of water, wood, plants, stone, and petrified wood. The characters are cut out of the copper plates.  Kryptos is not open to the public. 

Kryptos was created by the American artist Jim Sanborn, whose work combines sculpture, language, science, and cryptography in unique and thought-provoking ways. Over the years, I had the opportunity to meet Jim Sanborn on several occasions and exchange ideas about Kryptos, its hidden messages, and the remarkable community that has formed around the sculpture. These encounters offered valuable personal insights into one of the most fascinating works of cryptographic art ever created.

Over the years, a large and passionate community of Kryptos solvers has emerged, united by the challenge of deciphering the sculpture’s remaining secrets. The community is led by U.S. cryptography expert Elonka Dunin, a close friend with whom I have collaborated extensively, including co-authoring a book.

The encrypted inscription

The sculpture contains four encrypted sections, commonly referred to as K1, K2, K3, and K4. These sections are not visually separated from one another, creating the impression of a continuous encrypted text. K1, K2, and K3 have been successfully deciphered. The first known solution of these parts was achieved in 1992 by the National Security Agency, although this breakthrough was not publicly disclosed at the time. In 1998, David Stein, an employee of the Central Intelligence Agency who passed the sculpture almost daily on his way to work, independently solved K1, K2, and K3. This solution also remained unpublished at first.

In 1999, renowned cryptography expert Jim Gillogly independently solved K1, K2, and K3 and publicly released his findings. Only afterward did it become known that both the NSA and the CIA had successfully solved the same sections years earlier.

K4

                           OBKR
UOXOGHULBSOLIFBBWFLRVQQPRNGKSSO
TWTQSJQSSEKZZWATJKLUDIAWINFBNYP
VTTMZFPKWGDKZXTJCDIGKUHUAUEKCAR

Here is K4 on the sculpture:

Despite decades of analysis by professional cryptographers, intelligence agencies, mathematicians, and enthusiasts around the world, no definitive solution has yet been found — making K4 one of the most famous unsolved cryptographic puzzles in the world.

The Clues

Over the years, Jim Sanborn has provided four clues to solving K4. Each clue consists of one or more plaintext words and their positions:

• 2010: The sixty-fourth through sixty-ninth positions of K4 are BERLIN.
• 2014: The word CLOCK follows BERLIN in the K4 plaintext.2
• January 2020: The word NORTHEAST appears at positions 26 through 34.
• August 2020: An additional word, EAST, appears at position 22.

Here are the words in the encrypted text:

Decades after its installation, Kryptos continues to inspire cryptography enthusiasts around the world.