KRYPTOS ⌂

CIA headquarters · Langley, Virginia · 1990

KRYPTOS

A copper sculpture covered in about 1,800 letters, standing in a courtyard at the CIA. Three of its four messages were cracked in the 1990s. The fourth, K4, has resisted every public attempt for more than thirty years.

Start with K1 → Open the scratchboard
ArtistJim SanbornAmerican sculptor
Cipher designerEd ScheidtRetiring head of the CIA Cryptographic Center
Dedicated3 Nov 1990Cost about US$250,000
SolvedK1, K2, K3K4 still not public

The copper screen

The sculpture is an S-shaped wall of copper with letters cut right through it. The left half is the ciphertext: 869 characters across 28 lines, holding four messages one after another with no gap between them. The right half is the key table the sender would use: a Vigenère tableau built on the word KRYPTOS. Tap a section of the ciphertext to open its lesson.

Four messages, three ideas

Timeline

  1. Late 1980sJim Sanborn is commissioned to make a sculpture for the CIA’s new headquarters building. Ed Scheidt teaches him the encryption techniques used in it.
  2. 1990Kryptos is dedicated on 3 November. Scheidt expected it to take five to ten years to solve.
  3. 1992An NSA team led by Ken Miller quietly solves K1, K2 and K3. This is only revealed years later.
  4. 1998CIA analyst David Stein solves K1–K3 with pencil and paper and publishes it in an internal CIA newsletter.
  5. 1999Computer scientist Jim Gillogly announces the first public solution of K1–K3, helped by a computer.
  6. 2006Sanborn reveals he left an S out of K2. The ending changes from “…ID BY ROWS” to “…X LAYER TWO”.
  7. 2010K4 clue 1: letters 64–69 decrypt to BERLIN.
  8. 2014K4 clue 2: letters 70–74 decrypt to CLOCK, a nod to the Berlin World Clock.
  9. 2020K4 clues 3 and 4: letters 26–34 decrypt to NORTHEAST and letters 22–25 to EAST.
  10. 2025Journalists Jarett Kobek and Richard Byrne find scraps of the K4 plaintext in the Smithsonian archives. Sanborn confirms they are genuine and asks for them to stay sealed. The K4 solution and encryption tables are auctioned in November for US$962,500. The plaintext is still not public.

Sources: Wikipedia’s Kryptos article and Elonka Dunin’s transcript of the sculpture. Every solution on this site is decrypted live in your browser from that transcript.

Add a layer from the left, or try a recipe.