The Smithy code is a series of letters embedded, as a private amusement, within the April 2006 approved judgement of Mr Justice Peter Smith on ''

The Da Vinci Code ''The Da Vinci Code'' is a 2003 mystery thriller novel by Dan Brown. It is Brown's second novel to include the character Robert Langdon: the first was his 2000 novel ''Angels & Demons''. ''The Da Vinci Code'' follows symbologist Robert Langdon ...

'' copyright case. It was first broken, in the same month, by Dan Tench, a lawyer who writes on media issues for ''

The Guardian ''The Guardian'' is a British daily newspaper. It was founded in 1821 as ''The Manchester Guardian'', and changed its name in 1959. Along with its sister papers ''The Observer'' and ''The Guardian Weekly'', ''The Guardian'' is part of the Gu ...

'', after he received a series of email clues about it from Justice Smith.

How the code works

The letters in question are part of the actual text of the judgement, but italicised in contrast to the rest of the text. The following sequence of unusually emphasised letters can be extracted from the judgement document: The italicised letters only occur up to paragraph 43 (which is page 13 of a 71-page document). Meanwhile, paragraph 52 concludes with this sentence: "The key to solving the conundrum posed by this judgment is in reading HBHG and DVC." (These abbreviations are used by Smith throughout the judgement in referring to the books at issue, ''

The Holy Blood and the Holy Grail ''The Holy Blood and the Holy Grail'' (published as ''Holy Blood, Holy Grail'' in the United States) is a book by Michael Baigent, Richard Leigh (author), Richard Leigh, and Henry Lincoln. The book was first published in 1982 by Jonathan Cape in ...

'' and ''

''.) There are 70 sections in the judgement. The source words from the judgement for the letters (with intervening words removed):

Letter frequencies

Excluding leading letters "s m i t h y c o d e", the letter frequencies are as follows: * a – 4 * e – 3 * g, m, p, q, s, t – 2 * c, d, f, i, j, k, o, r, v, w, x, z – 1

Letter location

Paragraph numbers for cipher letters: * 1 Claimant(s) * 2 * 3 * 4 * 5 f(o)r * 6 * 7 * 8 * 9 * 11 * 13 * 14 * 16 * 18 (t)he * 19 * 20 * 21 u(s)ed * 23 w(a)s * 25 * 26 * 27 * 29 * 30 * 31 o(f) * 34 (k)ey * 35 * 37 * 38 * 40 * 42 * 43

Hints

From article "'Da Vinci' judgement code puzzles lawyers":

Solution

The cipher was a type of

polyalphabetic cipher A polyalphabetic cipher substitution, using multiple substitution alphabets. The Vigenère cipher is probably the best-known example of a polyalphabetic cipher, though it is a simplified special case. The Enigma machine is more complex but is sti ...

known as a

Variant Beaufort The Beaufort cipher, created by Sir Francis Beaufort, is a substitution cipher similar to the Vigenère cipher, with a slightly modified enciphering mechanism and tableau. Its most famous application was in a rotor-based cipher machine, the Hage ...

, using a keyword based on the

Fibonacci sequence In mathematics, the Fibonacci numbers, commonly denoted , form a integer sequence, sequence, the Fibonacci sequence, in which each number is the sum of the two preceding ones. The sequence commonly starts from 0 and 1, although some authors start ...

, namely AAYCEHMU. This is the reverse of the

Vigenère cipher The Vigenère cipher () is a method of encryption, encrypting alphabetic text by using a series of interwoven Caesar ciphers, based on the letters of a keyword. It employs a form of polyalphabetic cipher, polyalphabetic substitution. First desc ...

, which here enables decryption rather than encryption. Assigning each letter its place in the alphabet, the keyword corresponds to 1, 1, 25, 3, 5, 8, 13, 21. It is possible that the reason 25 (Y) was included is to denote a backward step of 2 rather than a forward step. It is a twist drawn from ''The Holy Blood and the Holy Grail'', and concerns the number 2 in the Fibonacci series, which becomes a requirement to count two letters back in the regular alphabet rather than a signal to use an alphabet that begins with B. For instance, the first E in the coded message, which corresponds to a 2 in the Fibonacci series, becomes a C in the answer. The 10th ciphertext letter, T, should really be an H, and there should also be a Z at the end of the ciphertext. The repetition of the digraph 'MQ', after 8 letters, suggested a key that was 8 letters long, which is in fact the case. (This type of attack on a cipher is known as a

Kasiski test In cryptanalysis, Kasiski examination (also referred to as Kasiski's test or Kasiski's method) is a method of attacking polyalphabetic substitution ciphers, such as the Vigenère cipher. It was first published by Friedrich Kasiski in 1863, but see ...

). The full plaintext should read: Although correct application of the cipher in reverse, to decrypt, actually yields: The algorithm for generating the plaintext from the ciphertext is: repeating the eight-letter key, add the relevant key letter to each plaintext letter, and then take a step one letter back. (Alternatively, as is done in a professional context, the letters of the alphabet may be numbered from 0, in which case the final step back does not have to be made). Jackie Fisher was a British admiral. "He was a driving force behind the development of the fast, all big-gun battleship, and chairman of the Committee on Designs which produced the outline design for the first modern battleship, HMS ''Dreadnought''."

References

External links

* The complete text of the judgment was formerly available at http://www.hmcourts-service.gov.uk/images/judgment-files/baigent_v_rhg_0406.pdf. **The archived copy of this text from 5 December 2006 can be foun
here
*, text of the judgment without the italics that mark out the cyphertext.

(lists the Smithy Code as solved)

- analyzes how the code is put together, and contains a link to a mirrored copy of the PDF of the original judgment * *
Tool to crack the code
{{Cryptography navbox , classical The Da Vinci Code History of cryptography Puzzles 2006 in law 2006 in the United Kingdom