Lorenz cipher

Abstract: Each summer since 2004, an intensive course in cryptology has been offered to college and university teachers at Bletchley Park under the auspices of the National Science Foundation's Chautauqua Short Course Program. This article provides an overview of the Chautauqua Program and describes the Bletchley Park course.

Abstract: In the field of the history of computing, the long-standing argument of whether it was the UK or the US that was first to produce an electronic computer is a well-known one, with opinion divided between the two depending on different terminology and interpretations of definitions of the term ‘computer’. It is indeed largely a moot point, both countries having achieved the same thing independently at very similar points in time, both as the result of a specific military driver: the US developed ENIAC in order to tackle a bottleneck in the production of firing tables urgently required in the field; the UK developed Colossus to decode messages in the Lorenz cipher used by the Nazi high command. Although built with different architectures, both machines shared a great deal in terms of construction and componentry, especially in the innovative use of electronic valves, which operated at more than one thousand times the speed of the electro-mechanical relays they replaced. Whereas the UK developments at Bletchley Park were understandably carried out in complete secrecy (and in fact were not made public for another 30 years), the US developments were, in contrast, widely known in academic circles through published papers and, once finally completed, ENIAC was presented to the general public. At this point, it was decided that the huge technological leaps made were, in themselves, not impressive enough for public consumption, and that an additional ‘visual display’ of the computing processes being performed was required. It is widely held that this move led to a long-lasting association of computers with displays of flashing lights, and influenced the representation of computers in the popular press, film and television for many years. There is indeed some evidence that well into the 1970s, computers were produced with flashing lights serving no other purpose than to impress an audience. This paper goes further, though, arguing that in fact, the early presentation of computing technology in the form of ENIAC had a direct causal influence on the design and presentation of the first commercial computers that followed it, and in turn, directly influenced the public’s expectation of the capability of electronic computers. In terms of the Social Construction of Technology this is important, as once a set of expectations is present in the minds of a relevant social group, it becomes a deciding factor in the acceptance of various forms of computers and therefore a driving force in the actual technological development of computers themselves.

Abstract: The German cipher traffic called tunny which was broken at Bletchley Park using the Colossus machine was produced bu an in-line “cipher-attachment” made by Lorenz, Schlussel Zusatz or SZ42. This paper is a description of the way that the SZ42 operates and its mechanism.