Computer Science and Cryptology: a Border Shift

Turing's work shows the close links between cryptology and mechanization of computation. Their parallel evolution is still shifting many borders: between secrecy and transparency, between public and private spheres, between social control and individual freedom, between art and science. This article explores this movement in light of the areas in which it has manifested. Since World War II, cryptology has evolved from an almost exclusively military use to its current ubiquity. This change in use has been accompanied by a transformation in nature, particularly in terms of its relation to science. Handicraft techniques have given way to a new branch of mathematics whose scientific character is as much claimed as controversial, as security is matter for speculation. The questions opened by the theory of complexity find a pictorial illustration with the virtual worlds of Russel Implagliazzo. The societal impact of cryptology is also approached from the point of view of the nature of the exchanges: institutional control or maintenance within private circles. The history of the opposition between state control and freedom of use will be exposed under the law. Finally, the new applications and threats of cryptology, pushing back the boundaries of what is possible, from cloud computing to virtual currencies are discussed.