
Spain cracks King Ferdinand's 500-year-old code - jonbaer
http://www.bbc.com/news/world-europe-42931940
======
jeioncs
The secret code of the letters of the Great Captain and Fernando the Catholic
that the CNI and the Army Museum announced yesterday to have deciphered, had
already been discovered previously. Gustave Bergenroth, a nineteenth-century
German Hispanist based in England, published his studies on the General
Archive of Simancas in the 'Calendar of State Papers, Spain, Volume 1,
1485-1509' in the year 1862. In the preface he explains his journey in the
archive and an introduction to how he deciphered the Spanish codes.

[https://www.elconfidencial.com/cultura/2018-02-03/codigo-
sec...](https://www.elconfidencial.com/cultura/2018-02-03/codigo-secreto-gran-
capitan-gustave-bergenroth_1516192/)

A known mistery

~~~
fovc
Link is in Spanish. I found the linked blog post from the physics professor
who first noticed that the code had been previously cracked more interesting
and informative (also in Spanish):
[http://elprofedefisica.naukas.com/2018/02/02/el-cni-y-el-
no-...](http://elprofedefisica.naukas.com/2018/02/02/el-cni-y-el-no-tan-
secreto-codigo-del-gran-capitan/)

~~~
dmix
Interesting, here's a good quote beyond the fact that it was already
deciphered a century ago (by a 19th century historian, not a cryptanalyst
working for a 3 letter agency in 2018):

> First, and contrary to what ABC says, this code is not very sophisticated.
> It is a monoalphabetic substitution system with homophones to which a set of
> terms of agreed language has been added. I have a handful of Spanish codes
> of the time and I can assure you that there are more sophisticated codes
> than this one. For example, the so-called Clave de los Capitulaciones is
> similar in form and structure, being at least ten years older; and the
> General Figure of the Catholic Kings, dated similar to that of the Great
> Captain, had no less than 670 terms in agreed language.

> Third, these types of keys were already vulnerable to cryptanalytic attacks
> at that time. Manias such as encrypting only part of the letter, or
> repeating the used encrypted terms, made them relatively easy to decipher by
> unauthorized users.

There's also a pictures of what the deciphered key looks like both in the
1800s version on old paper and the CNI's version on graph paper which is
interesting.

~~~
azinman2
Link to the photos?

~~~
dmix
1852 = [http://elprofedefisica.naukas.com/files/2018/02/Clave-
Gran-C...](http://elprofedefisica.naukas.com/files/2018/02/Clave-Gran-
Capitan-1.jpg)

2018 = [http://elprofedefisica.naukas.com/files/2018/02/Clave-
Gran-C...](http://elprofedefisica.naukas.com/files/2018/02/Clave-Gran-
Capitan-2.jpg)

~~~
azinman2
Neat!

------
moyix
One of my Italian professors from undergrad, Marcello Simonetta, also cracked
a 500 year-old code. He found an encrypted letter [1] sent by Federico da
Montefeltro, the Duke of Urbino, that showed he had helped orchestrate the
Pazzi conspiracy [2] to assassinate Lorenzo de' Medici.

Interestingly, to break the code he relied on a code-breaking manual written
by one of his own ancestors, Cicco Simonetta [3]! When I first learned about
this, I thought it was incredibly silly that he didn't ask a modern
cryptographer for help. But in some ways, Cicco's manual, written around the
same time, is more useful: it focuses on precisely the kind of codes that
would have been used for the letter, and the techniques it describes are
reasonably effective (essentially frequency analysis, with some specific
tricks for documents written in Latin or Italian). And it is certainly more
narratively satisfying that he ended up breaking it on his own, following his
ancestor's manual!

If you want to know more, he wrote a book on the subject:

[https://www.amazon.com/dp/B001AL6656/](https://www.amazon.com/dp/B001AL6656/)

And as another fun bit of trivia, he ended up consulting on the historical
aspects of Assassin's Creed II, which takes place in Florence around the time
of the Pazzi conspiracy!

[1]
[http://www.nytimes.com/2004/03/06/books/1478-assassination-s...](http://www.nytimes.com/2004/03/06/books/1478-assassination-
solved-the-humanist-did-it.html)

[2]
[https://en.wikipedia.org/wiki/Pazzi_conspiracy](https://en.wikipedia.org/wiki/Pazzi_conspiracy)

[3] [http://cipherfoundation.org/older-ciphers/voynich-
manuscript...](http://cipherfoundation.org/older-ciphers/voynich-
manuscript/cicco-simonettas-regule/cicco-simonettas-treatise-decipherment/)

------
orblivion
Any code more than 50 years old should be trivial to crack by modern
cryptoanalysis right? Otherwise we wouldn't be told to only use the very best
algos we have on hand. It must have just been a matter of taking the time to
crack this particular code.

On a side note, (as long as they mention Rosetta Stone) does writing in
another language count as a form of cryptography? If so, it should likewise be
trivial to crack any remaining unknown ancient scripts.

But I'm probably being ignorant somewhere here.

~~~
widdershins
I think use of other languages could be described as a form of cryptography.
It's been done before as well - see the Navajo code talkers in WWII[1], who
were very effective in terms of speed, and who the Japanese found difficult to
even transcribe. Of course, this relies on the language being obscure, and
many more languages are well documented now than in the 1940s.

>it should likewise be trivial to crack any remaining unknown ancient scripts

That doesn't follow. Part of successfully decrypting a message is knowing when
you have the right answer. That doesn't apply if you're looking at a limited
dataset (or claytablet set), and you have no idea about the context the texts
were written in.

[1]
[https://en.wikipedia.org/wiki/Code_talker](https://en.wikipedia.org/wiki/Code_talker)

~~~
orblivion
This feels like it flies in the face of the usual advice for modern crypto.
Don't try to be clever. Don't roll your own system. But it sounds like a novel
language, and a lack of context, could actually cause headaches for those
coming after you.

~~~
Piskvorrr
With the possible exception of OTP, modern (sic) crypto was essentially
nascent at that time (Enigma), there was no option but to roll your own. Your
advice comes from a corpus of 70 years of collective experience which did not
exist 70 years ago.

~~~
orblivion
I think when I said this I was assuming that the implication was that it would
be useful even today. I understand that crypto was much different back then.

------
relyks
It'd be cool if they let you in on how the code was deciphered. Does anyone
know of any sources that discuss the process? Sounds like in this case
frequency analysis wouldn't have cut it :D

~~~
icot
The original document by G. Bergenroth mentioned in the link provided by
jeioncs is supposed to have a description of the original procedure. I don't
know how/if you can get a document from the National Archives of the United
Kingdom, though.

Edit: Link to the actual Archives entry:
[http://discovery.nationalarchives.gov.uk/details/r/C12056](http://discovery.nationalarchives.gov.uk/details/r/C12056)

~~~
hordeallergy
I live a five minute walk from the archives, they're open to all, but closed
today.

------
walshemj
You have to wonder if deep in the vaults of GCHQ there are not records going
back that long :-)

