A Goldmine of GCCS and GCHQ Records (1914-1979)

September 13, 2009
The National Archives

The National Archives

Many thanks to Mike Cowan for a link to an internal sub-tree of The National Archives (UK) with a plethora of links to valuable cryptographic material related to the Government Code and Cypher School (GCCS) and Government Communications Headquarters (GCHQ) between the years 1914-1979.

Quoting from the web site, the site contains “general records of the Government Code and Cypher School (GCCS) and Government Communications Headquarters (GCHQ) relating to responsibilities for intercepting enemy communications, particularly during the Second World War, and for ensuring security of the government’s electronic communications“.

The records span the years 1914-1979 and included the following general categories:

  • Senior management papers
  • Soviet communications
  • Japanese military communications
  • Histories and personal papers
  • German military communications
  • Bulgarian, Croatian, French, Iranian, Italian Portuguese and Spanish communications
  • Diplomatic, commercial and meteorological communications
  • Liaison with allied organisations
  • Communications security
  • Field signals intelligence
  • Technical matters
  • Intercepted plain language communications
  • Wireless Telegraph Section
  • GC&CS Administration
  • Research Section

For those with access to the National Archives in London, there is material here to keep one busy for years.


Serious about cryptanalysis? Learn a programming language!

June 30, 2009
Example of cryptanalytic program written in Perl

Cryptanalytic program written in Perl

I’ve been a computer programmer since the early 70’s, about the time I became enamoured with cryptanalysis.  Writing computer programs to aid my cryptanalytic research has been invaluable to me throughout this entire period.  Sure, I have spent delectable hours solving ACA-type cryptograms by hand.  When I worked on more serious ciphers in university, however, computers have always been invaluable and time-saving. Read the rest of this entry »


A Superb Cryptanalytical Guide to the Enigma Cipher Machine

April 24, 2009

Over the years I’ve come across many articles explaining how the Enigma cipher machine works. All too often I would feel, as a cryptanalyst, that many of the articles glossed over important features or handled them poorly.

Well, if you’re looking for an in-depth explanation of the Enigma, complete with a lucid mechanical description and mathematical underpinnings you can really sink your teeth into (and understand!) look no further. Check out Erik Vestergaard’s superb explanation of the Enigma’s mechanical, operational, and mathematical aspects. A Danish high school mathematics teacher, Vestergaard took his class on a study tour to London in 2007, and one of their stops included Bletchley Park. This site is a wonderful compilation of their experience in Bletchley, complete with mouth-watering, clear descriptions of how the Enigma works and how it was broken. Here’s a list of topics covered: Read the rest of this entry »


Cryptographically-Challenged Cryptographers

March 5, 2009

In a recent posting on the Cipher Mysteries blog, Nick Pelling provides a list of contemporary cipher challenges he collected from the Web.  One of those listed is by one Andrew Fergus, who posted his own supposedly unbreakable cipher which apparently uses a pseudo-random number generator for encryption.  As Mr. Fergus proclaims, “I have spent some time developing a cipher, which I genuinely believe is unbreakable”.

What left me in a state of disbelief was the following gem found on Mr. Fergus’s site: Read the rest of this entry »


Announcing the Chaocipher Clearing House

February 27, 2009

Since my early teens (back in the early 70’s) I’ve been fascinated by the art and science of cryptography and cryptanalysis.  It was in David Kahn’s magnum opus “The Codebreakers” that I was first introduced to the Chaocipher. Read the rest of this entry »