| Dear
Press Office,
As discussed on the phone this morning, I am writing with details of a Cipher I am researching and on which I would be very obliged for any information that GCHQ can release to me from their archives. The cipher is called Chaocipher and it was invented by John F Byrne in 1920 and publicised in his book 'Silent Years'. (Details appended.) It is a machine cipher and Byrne has not openly disclosed the machine design nor the nature of the keys. Instead he supplied lengthy plaintext and matching ciphertext, and challenged cryptanalysts to deduce how the machine works. To date this has not been achieved, at least not in the public domain. In 1922 Byrne, an American of Irish extraction, submitted information on his cipher and a model of his machine to William F. Friedman, then a cryptanalyst in the Military Intelligence Division of the U.S. War Office in Washington. The model was returned after Friedman requested 50 enciphered messages of about 25 words each, to which Byrne apparently did not respond. In 1937 Byrne approached the US Navy department with a booklet and a working model but no interest was evoked. If in GCHQ archives there is any record of this cipher I would much appreciate a copy of material that can be made available. With many thanks, Michael J. Cowan. . . . Some more details of Chaocipher: J. F. Byrne's autobiography "Silent Years: An Autobiography with Memoirs of James Joyce and Our Ireland", published in 1953 tells the story of his cryptographic invention he called "Chaocipher" in Chapter 21. He relates the history of his invention, his attempts to interest numerous organizations and concludes with 23 pages of corresponding plaintext and ciphertext enciphered using the Chaocipher system. |
| We
have absolutely nothing in our archives about Chaocipher, and nothing
to suggest that anybody at GCHQ (or GC&CS, as we were called
from 1919
to 1946) has ever spent time looking at it.
This is not an absolute negative: all relevant surviving GCHQ files dated 15 August 1945 or earlier (as well as a small amount of subsequent material) have been released to The National Archives where they can be found in Class HW. Details of HW can be found here: http://www.nationalarchives.gov.uk/catalogue/displaycataloguedetails.asp?CATID=781&CATLN=2&Highlight=&FullDetails=True I should warn you that this represents an enormous amount of material, and I would be extremely surprised if it contained anything about Chaocipher. If the system was offered to the US Signals Corps, might it have been offered to the British Armed Forces? GC&CS's was responsible for providing advice on the security of UK governmental and military communications but such advice was not always sought. |
| Interval of 7 | Interval of 8 | Percentage |
| 0 | 0 | 24% |
| >0 | 0 | 2% |
| 0 | >0 | 62% |
| 1 | 1 | 12% |
Mr. Rubin, This responds to the Freedom of Information Act (FOIA) request you submitted via the Internet on 2 August 2009, which was received by this office on 3 August 2009. In your request, you state that you "would like to know what the disposition of FOIA Case 58395 was: 'Granted in Full', 'Partial Denial', or any other disposition?" For tracking purposes, your 2 August 2009 request has been assigned FOIA Case 59326. We are not processing your submission as a FOIA request as it does not ask for specific Agency records. However, as a courtesy, we provide you the following explanation: FOIA Case 58395 was a previous FOIA request from you dated 21 March 2009. In that request, you asked for records related to John F. Byrne's "Chaocipher" machine device. We conducted a search and located only one document, a segment of a book written by Mr.Byrne. This document was released by NSA in a previous FOIA request. Since this was the only document NSA located and since it was released in full, your FOIA Case 58395 was closed as a "Granted in Full." Very Respectfully, Marianne StuparPOC, FOIA Requester Service Center National Security Agency |