During
America's first century, secret writing - cryptography - figured
in many instances in which lives and fortunes were at
stake and confidentiality was desired. Until nearly the
middle of the 19th century, large armies moved over an
extensive battlefield unassisted by any special technology
to aid long distance communications or even tactical
communications. By the same token, there was no reliable
way for one side to obtain a steady source of enemy message
traffic for intelligence purposes; collection was dependent
on the capture of enemy transports or the deliberate
apprehending of an enemy courier.
A partial answer came in 1844, when Samuel F. B. Morse successfully tested his improved electromagnetic telegraph between Washington and Baltimore. At the time of the American Civil War, both sides began encrypting high-level messages to be transmitted on the telegraph. More importantly, for the first time it became possible to collect such messages from the enemy in volume and in near real-time. Further, both sides established cipher bureaus in their respective capitals to work on enemy encrypted messages, one of the early examples of a centralized intelligence activity in the United States.