ABSTRACT
In considering the history of signals intelligence (SIGINT), it quickly becomes apparent that this particular element of the modern intelligence-gathering capability is intimately connected with another, much older science, in the shape of cryptography. In one sense, the history of modern SIGINT as we know it today can only have begun with the emergence of the first electronic methods for transmitting signals from one place to another. In 1838, Samuel Morse demonstrated the method for sending a series of pulses down a cable (these formed the basis of the Morse Code); five years later, work began on the first experimental telegraphic line, between Washington, DC, and Baltimore in the US. Thus began the method for sending messages over long distances, and the birth of cable telegraphy. As with many advances in science, the intelligence implications of this development were born almost simultaneously, as governments considered how to eavesdrop of their adversaries’ telegraphic messages.
