Kryptos K4: Solved
The full 97-character plaintext, a closed cipher mechanism verified at every position, all four artist-confirmed anchors preserved — and now fully solvable on-site with only pen, paper, and a calculator.
What is Kryptos?
Kryptos is an encrypted sculpture at CIA headquarters in Langley, Virginia, created by artist Jim Sanborn and installed in 1990. It contains four encrypted messages. Three were solved in the 1990s. The fourth — K4 — is 97 characters that resisted every cryptanalytic attempt for over 35 years.
The K4 plaintext
The complete solved plaintext, preserving all four artist-confirmed anchors at their documented positions:
THE COMPASS ROSE IS HERE X EAST NORTHEAST THIS IS YOUR POSITION X COMMISSION BERLIN CLOCK WHICH IS NORTHEAST OF HERE X
THECOMPASSROSEISHEREXEASTNORTHEASTTHISISYOURPOSITIONXCOMMISSIONBERLINCLOCKWHICHISNORTHEASTOFHEREX
K4 is a double-keyed Vigenère cipher. The KRYPTOS tableau on the sculpture is the cipher machine. Two keys (f and g) disguise entry into the tableau; one final gate correction produces the shift. P = (C − R) mod 26 holds at all 97 positions. No secondary key, no hidden layer, no affine correction is required.
"I want to understand the sculpture"
Start with what Kryptos is, walk the physical clues on-site, then see the K4 plaintext in context.
"Show me the solution"
Go straight to the K4 plaintext with plain-English explanation, then verify the math position by position.
"I want to check the math"
Examine the cipher mechanism step by step, then independently verify every position with downloadable data.
New: On-Site Field Guide
Every clue mapped. Every constant sourced. The complete 8-step procedure to decrypt K4 standing at the sculpture with nothing but pen, paper, and a calculator. No external charts required.
About the author
Matt Lacy is an independent cryptanalysis researcher and IT professional based in Ohio. SolveKryptos documents a multi-year structural reconstruction of K4, preserving confirmed anchors and publishing falsifiable claims for public review. The full verification dataset is available for download.