For anyone that is as excited about cyphers and puzzles, you might be familiar with the still partially unsolved Kryptos cypher.

If you’re unaware: Kryptos is a distributed sculpture at the CIA headquarters by Jim Sanborn. The main part of the sculpture contains a set of letters from the alphabet, which encodes (at least) 4 passages, also called K1, K2, k3 and k4. K1-3 have been solved a long time ago, but k4 is still unsolved to this day. There are also a couple of texts in morse code, often referred to as k0.

meanings of k0

The morse code texts are as follows:

1. E E VIRTUALLY E

   E E E E E E INVISIBLE

2. DIGETAL E E E

   INTERPRETATIT

3. E E SHADOW E E

   FORCES E E E E E

4. LUCID E E E

   MEMORY E

5. T IS YOUR

   POSITION E

6. SOS
7. RQ

k1: Clue 1, 4 and possibly 3.

To solve k1, two keywords are needed: “Kryptos” and “Palimpsest”. The keyword “Kryptos” is part of the keyed Vigenère encryption tableau on the right hand of the sculpture. The other keyword was found by brute-force, and Sanborn previously said that that was not the intended way to solve the cypher. If we work back from the definition of “Palimpsest”, we can find the corresponding clues for k1. In this case, “Virtually Invisible” and “Lucid memory” are probably clues for this keyword. “Shadow forces” might also be a clue for k1, but it might also be related to the compass and lodestone.

k2: Clue 5

To solve k2, two keywords are needed: “Kryptos” and “Abscissa”. The keyword “Kryptos” is still a part of the keyed Vigenère encryption tableau on the right hand of the sculpture. For Abscissa, we can consider the clue “T is your position” as related.

k3: Clue 3?

To solve k3, none of the clues seem to help in actually solving the cypher the correct way. The decoded text is related to clue 3 though.

k4: the unsolved cypher

As k4 has been unsolved for so long, there have been four sets of clues given by Sanborn. In the matrix below I’ve put the characters for k4, with below the deciphered characters. Below that I’ve put the shortest distance between the two, and if the letter is ahead or behind the deciphered letter.

O

B

K

R

U

O

X

O

G

H

U

L

B

S

O

L

I

F

B

B

W

F

L

R

V

Q

Q

P

R

N

G

K

S

S

O

E

A

S

T

N

O

R

T

H

E

A

S

T

-1

11

1

-2

-3

-2

1

2

-6

-2

-10

0

1

-

+

+

-

-

-

+

+

-

-

-

+

+

T

W

T

Q

S

J

Q

S

S

E

K

Z

Z

W

A

T

J

K

L

U

D

I

A

W

I

N

F

B

N

Y

P

B

E

R

-12

6

2

-

+

+

V

T

T

M

Z

F

P

K

W

G

D

K

Z

X

T

J

C

D

I

G

K

U

H

U

A

U

E

K

C

A

R

L

I

N

C

L

O

C

K

-10

-10

-5

-9

12

9

13

0

-

-

-

-

+

+

+

+

Remaining: K4 and Clues 2, 6 & 7

Then two connections I haven’t seen made before:

For the EASTNORTHEAST sequence, there is a repeating sequence of +—+ relations between the encrypted/decrypted character. Clue 6, the morse code for SOS(…___…) might be a clue that could have pointed here.

RQ could mean anything, but in math it could point to Irrational numbers, as it is R - Q (Real numbers without the rational numbers). The morse above contains a bunch of padding e characters, similarly in how k2 contained a bunch of padding “x” characters where “Abscissa” was the keyword. e is an irrational number, so could that point to having to use e to decipher k4?