The Meridian Key: Decrypting Kryptos K4 Through an Enigma-Uhr Model

This paper proposes a decryption of the fourth and final section (K4) of Jim Sanborn's Kryptos sculpture at CIA Headquarters, Langley, Virginia. The method applies an Enigma-Uhr (clock-augmented Enigma) mechanism using two rotors (designated A and R) with the keyphrase BERLINCLOCK as a dynamic Steckerbrett driver. The resulting plaintext yields geographic coordinates (74°55'24"N) that, when combined with the longitude established in the already-solved K2 section (77°08'44"W), lock onto a single meridian connecting CIA Headquarters to the Franklin Cenotaph on Devon Island in the Canadian High Arctic. The structural alignment between two independent sections of the sculpture along a single line of longitude, combined with the historical and thematic coherence of the endpoint, constitutes the primary evidence for the proposed solution.