In 1945 Claude Shannon wrote a paper for Bell Telephone Labs about applying information theory to cryptography. This work was not publically disclosed until a shorter, declassified version was produced in 1949. A digital scan of the original 1945 version, along with many other papers of Shannon, was made available in 2013 by N. J. A. Sloane and Aaron D. Wyner (see Claude Elwood Shannon, Miscellaneous Writings).
The scanned pages of the typewritten document seem anachronistic today, and IACR fellow Whitfield Diffie and John O'Rourke undertook the task of re-typesetting the document in modern fonts using LaTeX. The resulting work is available here courtesy of Alcatel-Lucent.