A consideration of the application of cryptographic techniques to data processing
R. O. Skatrud · 1969
Two digital cryptographic techniques are described which may have potential applications in Data Processing Systems. A method of digital substitution analogous to a Vernan double tape system is presented, using a controlled combination of data and the contents of two memories. The second method uses a digital route transposition matrix using a combination of row and column transposition under memory control. Possible ways of achieving key leverage in each ciphering process are described.