Source: https://www.scientificamerican.com/article/a-solution-to-the-cias-kryptos-code-is-found-after-35-years/ From the post: >>After a 35-year quest, the final solution to a famous puzzle called Kryptos has been found. Two writers discovered the fourth answer to the code hidden among the Smithsonian Institution’s archives. The puzzle, a copper sculpture engraved with four coded messages, has fascinated professional and amateur cryptographers since 1990, when artist Jim Sanborn installed it at the CIA’s headquarters in Virginia. The four encrypted messages are made up of 869 characters. The final section, K4, begins with “OBKR” and contains 97 letters. To claim a solution, one must show how they decoded it from that ciphertext. The first three passages were solved during the 1990s, but the solution to the fourth, known as K4, had remained secret until now.