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.

When we say "solve K4," we mean turn those 97 scrambled letters back into the real English sentence they are hiding. This page shows you how that works, and walks you through reading one letter from start to finish.

The big idea: the sculpture is the key

Most codes need a secret password to unlock them. K4 is different. The thing that unlocks it is 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 how to fix the front letter.

So you never need an outside password. Everything you need is printed on the statue. That is why we say: the sculpture is the 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

On the sculpture there is a Latin phrase, SUB UMBRA FLOREO. It means "under the shade I flourish." It has exactly 14 letters:

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, because K4's letters are arranged in 14 columns. Same width. The phrase lines up perfectly across the columns, like a stencil laid over a grid.

The "shadow stencil" is just 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 printable field card has the whole stencil on it, ready to carry to the sculpture.

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.
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 on the field card.

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. Anyone solving K4 has to land those exact words in those exact spots. Our method 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."

Take it to the sculpture

The field card is a single printable page with the KRYPTOS alphabet, the full shadow stencil, and these five steps. Print it, fold it in your pocket, and you can read K4 standing right in front of the statue.

Remember it in one sentence

The sculpture is the key. Read the front letter, walk to the back for the helper letter, look up the shift number, add the stencil's 1 or 0, then count backward. Out comes the real message.

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