Communication Theory of Secrecy Systems
is a paper published by Claude Shannon
from the viewpoint of information theory
. It is one of the foundational treatments (arguably the
foundational treatment) of modern cryptography. It is also a proof that all theoretically unbreakable ciphers must have the same requirements as the one-time pad
Shannon published an earlier version of this research in the classified report A Mathematical Theory of Cryptography, Memorandum MM 45-110-02, Sept. 1, 1945, Bell Laboratories. This classified report also precedes the publication of his "A Mathematical Theory of Communication", which appeared in 1948.
- Shannon, Claude. "Communication Theory of Secrecy Systems", Bell System Technical Journal, vol.28(4), page 656–715, 1949.