The Smithy Code

Summary

In April 2006, as part of the trial ruling of a plagiarism trial about the book ''The Da Vinci Code'', the judge in the case, Justice Peter Smith embedded his own secret code in the 71-page trial ruling (pdf) (pdf mirror). Once the code was discovered by a London legal analyst, it sparked off a worldwide race to see who could crack the code first. According to The Guardian, it was solved by Dan Tench, the legal analyst who first discovered the code, after he received a series of email hints from the judge.

The Kryptos Group was one of the entities searching for a solution to the Smihy Code. Though we were not the first to solve it, here is our final report on how the code can be cracked:

Ciphertext

The first two words, Smithy code are in English, but then the code switches to a different system, involving polyalphabetic substitution.

Method of decryption

The Judge used one of the methods of encryption described in the book The Da Vinci Code, via the Fibonacci Sequence. In the book, the fibonacci sequence in the Da Vinci Code starts off scrambled:

13-3-2-21-1-1-8-5

1-1-2-3-5-8-13-21 

(each number is the sum of the two preceding numbers) This numeric key can then be converted to an alphabetic key, as follows. first, convert the above sequence into letters, by numbering the alphabet:

         1         2
12345678901234567890123456
ABCDEFGHIJKLMNOPQRSTUVWXYZ

1-1-2-3-5-8-13-21

therefore becomes:

A-A-B-C-E-H-M-U

In other words, a key of "Fibonacci Sequence", could be described as using a key of AABCEHMU.

However, there is another twist. The Smithy Code didn't use a key of AABCEHMU, it instead used a key of AAYCEHMU

Here is another way of describing this: the key of AABCEHMU could also be written in more typical "Kryptos" fashion, as a series of Caesar shifts. Reading the below leftmost column, gives us our AABCEHMU key.

ABCDEFGHIJKLMNOPQRSTUVWXYZ
ABCDEFGHIJKLMNOPQRSTUVWXYZ
BCDEFGHIJKLMNOPQRSTUVWXYZA
CDEFGHIJKLMNOPQRSTUVWXYZAB
EFGHIJKLMNOPQRSTUVWXYZABCD
HIJKLMNOPQRSTUVWXYZABCDEFG
MNOPQRSTUVWXYZABCDEFGHIJKL
UVWXYZABCDEFGHIJKLMNOPQRST

However, the Judge didn't use the above matrix, he instead used the key of AAYCEHMU:

ABCDEFGHIJKLMNOPQRSTUVWXYZ
ABCDEFGHIJKLMNOPQRSTUVWXYZ
YZABCDEFGHIJKLMNOPQRSTUVWX
CDEFGHIJKLMNOPQRSTUVWXYZAB
EFGHIJKLMNOPQRSTUVWXYZABCD
HIJKLMNOPQRSTUVWXYZABCDEFG
MNOPQRSTUVWXYZABCDEFGHIJKL
UVWXYZABCDEFGHIJKLMNOPQRST

Further, he then added another twist. In classical Vigenere polyalphabetic cryptography, the letters of a plaintext message are applied to the plaintext alphabet along the top of the grid, and then checking for the location in the grid to get the ciphertext. However, with the judge's method, he instead started at the grid to find the plaintext letter, and then traced up to the top alphabet to get the ciphertext. This method is sometimes called a "Beaufort Variant".

Using the judge's method, and the first eight characters of plaintext JACKIEFI, encrypting each letter from a different line:

  abcdefghijklmnopqrstuvwxyz
1 ABCDEFGHIJKLMNOPQRSTUVWXYZ  J -> j
2 ABCDEFGHIJKLMNOPQRSTUVWXYZ  A -> a
3 YZABCDEFGHIJKLMNOPQRSTUVWX  C -> e
4 CDEFGHIJKLMNOPQRSTUVWXYZAB  K -> i
5 EFGHIJKLMNOPQRSTUVWXYZABCD  I -> e
6 HIJKLMNOPQRSTUVWXYZABCDEFG  E -> x
7 MNOPQRSTUVWXYZABCDEFGHIJKL  F -> t
8 UVWXYZABCDEFGHIJKLMNOPQRST  I -> o

And then for the next 8 letters, repeat and repeat and so on:

J A C K I E F I   S H E R W H O A    R E Y O U D R E    A D N O U G H T
j a e i e x t o   s T g p s a c g    r e a m q w f k    a d p m q z v -

Solution

This is a reference to Admiral Jackie Fisher, the second-most famous admiral in the British Navy. The judge was a big enough fan of Admiral Fisher that he actually named him in his own "Who's Who" biography. Fisher was a driving force behind the development of the first modern battleship, the Dreadnought, the first one of which was launched in 1906. Since the Da Vinci Code trial took place in 2006, the hundred-year-anniversary of this event, the Judge decided to commemorate it by inserting a code into his ruling.

Errors/quirks:

• One of the ciphertext letters is wrong. The second "T" should've been an "H".
• The last letter did not get enciphered into the legal document
• That 3rd line in the grid/matrix was shifted right by two instead of left by one. Either a deliberate obfuscation, or the Judge got confused. It is not uncommon for cryptographers to accidentally insert errors into ciphertext messages -- the amount of detail is considerable. Consider the likelihood that there will be typos and spelling errors even in any plaintext English document, and it is easy to understand how errors are even harder to catch when dealing with encrypted text.

Congratulations

Contact information

For any questions, or to obtain contact information for interviews, please contact one of the Kryptos Group moderators:

• Elonka Dunin: elonka@aol.com
• Chris Hanson: xenon@3dnature.com

The Kryptos Group