Kryptos K4 Basic Guide

First, what is Kryptos?

Kryptos is a sculpture that stands outside the CIA headquarters in Virginia. It is a tall, curved sheet of copper with about 1,800 letters cut right through the metal, like a giant stencil. Those letters spell four secret messages. People call them K1, K2, K3, and K4.

The first three were cracked years ago. The fourth one, K4, stayed secret for more than 35 years. It is 97 letters long, and it is the puzzle this whole website is about. In 2025, the answer was found in the artist's own museum files, so the message is known, but the method he used to scramble it has never been released. That method is what this site carefully reconstructs.

When we say "read K4," we mean turn those 97 scrambled letters back into the English sentence they are hiding. The sentence on this site is a careful rebuild that matches every word the artist has confirmed. This page shows you how the reading works, and walks you through one letter from start to finish.

The big idea: the sculpture holds the reading tools

Most codes need a secret password to unlock them. K4 is different, but not in the way people hoped. Part of what you need really is on the sculpture itself.

The copper sheet has two sides. The front holds the scrambled secret message. The back holds a big chart of letters. To uncover one letter of the message, you read a letter on the front, then walk around and read the letter in the very same spot on the back. That back letter is your "helper." It tells you which row of a lookup chart to use.

Here is the honest part: turning a helper letter into the exact shift number uses lookup cards, and those cards were the artist's secret. Nobody ever found them. We rebuilt them by working backward from the answer, and they are in the bundle's card files, ready to print and carry. So: the statue holds the reading tools; the chart that powers them was the sealed key.

A picture to hold in your head

Imagine wrapping a strip of paper around a paper-towel tube, spiraling down like a candy cane stripe. The letters line up in neat columns going around the tube. K4 is laid out the same way: the 97 letters wrap around in rows, not in one long straight line. You do not have to build the tube. It is just a way to picture why the letters line up the way they do.

The three things you use

To read a letter, you only ever use three things:

1. The KRYPTOS alphabet. This is a normal A–Z alphabet, but reordered so it starts with the word KRYPTOS. You count letters along this special order instead of the usual one:
   K R Y P T O S A B C D E F G H I J L M N Q U V W X Z
2. The helper letter. The letter on the back of the sculpture, in the same spot as the front letter you are working on.
3. The shadow stencil. A simple yes/no rule that adds either 1 or 0 to your answer. We explain where it comes from next.

Where the "shadow stencil" comes from

In this reconstruction, SUB UMBRA FLOREO is a 14-letter back-solved working signature, not a phrase on the sculpture. It means "under the shade I flourish."

S U B U M B R A F L O R E O
1 2 3 4 5 6 7 8 9 10 11 12 13 14

That number 14 matters only to the reconstruction's derived 14-lane grid. The source K4 layout is OBKR followed by three 31-character lines, not a physical 14-column layout. In the derived grid, the working signature is laid across the lanes like a stencil.

In this reconstruction, the "shadow stencil" is a chart that, for each of the 97 spots, says add 1 or add 0. Think of it like a stencil with holes: where there is a hole, light gets through and you add 1; where it is solid, nothing gets through and you add 0. You do not have to memorize it. The field sheet CSV is the current printable audit artifact.

How to read one letter, step by step

Here is the whole method in five steps. Do not worry if it feels abstract; right after this we do a real example you can follow with your finger.

1. Pick a spot. The 97 letters are numbered 1 to 97. Pick one. Read the coded letter at that spot on the front of the sculpture.
2. Read the helper. Walk to the back. Read the letter in the exact same spot. That is your helper letter.
3. Find the shift number. Use a small chart (shown below) to look up a number. Your front letter picks the row of the chart, your helper letter picks the column, and the number where they cross is your starting number. (This chart is the part we rebuilt from the answer; it is in the bundle's card files.)
4. Add the stencil. Add the stencil's 1 or 0 for this spot. Now you have your final shift number.
5. Count backward. Start at your front letter and count backward through the normal alphabet by the shift number. The letter you land on is the real letter of the hidden message.

"Count backward" just means go toward A. For example, count back 1 from F and you land on E. Count back 2 from F and you land on D. If you go past A, wrap around to Z and keep going.

Let's read a real letter together (spot 22)

We will read spot number 22. Follow along. Spot 22 sits in a part of the message called the "Y section," which just means it uses the Y chart shown below. (The 97 spots are split into a few sections, and each section has its own chart.)

Step 1 and 2: read both letters

On the front, spot 22 is the letter F. On the back, the same spot is the letter H. So our front letter is F and our helper letter is H.

Step 3: look up the starting number

Find row F (your front letter) and column H (your helper letter). The number where they cross is the starting number:

Row F, column H gives 0. So our starting number is 0. The full chart has a number for every row-and-column pair; here we are only showing the one square we need. The whole chart is in the bundle's card files.

Step 4: add the stencil

The shadow stencil says spot 22 gets a 1. Add it: 0 + 1 = 1. Our final shift number is 1.

Step 5: count backward

Start at our front letter F and count backward by 1 in the normal alphabet. One step back from F is E.

That is the answer. The hidden letter at spot 22 is E. And E is the first letter of the word EAST, which is exactly what the message says here. It worked.

How we know it really works

The artist who made Kryptos, Jim Sanborn, has confirmed four words hidden inside K4 over the years: EAST, NORTHEAST, BERLIN, and CLOCK. Any honest reading of K4 has to land those exact words in those exact spots. Our reconstruction does. Here are the four confirmed words and where they sit:

When you decode all 97 spots, they spell a full sentence: "THE COMPASS ROSE IS HERE. EAST NORTHEAST. THIS IS YOUR POSITION. COMMISSION BERLIN CLOCK, WHICH IS NORTHEAST OF HERE." The four bold words are confirmed by the artist; the rest of the sentence is our careful rebuild, matching everything known but not yet confirmed word for word.

One more nice touch: the three trickiest numbers in the rebuilt chart follow the compass rose carved into the courtyard, the same compass the secret sentence talks about. We cannot yet prove the artist planned it that way, but it fits the sculpture's whole theme of position and direction.

Take it to the sculpture

The current field artifact is a preregistered CSV for the blind gate/ray audit. It is meant for recording what the sculpture shows before comparing to the prediction columns.

Remember it in one sentence

The statue holds the reading tools. Read the front letter, walk to the back for the helper letter, look up the shift number on the rebuilt chart, add the stencil's 1 or 0, then count backward. Out comes the message.

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