[Cryptography] On improving the performance of the classical Playfair cipher

mok-kong shen mok-kong.shen at t-online.de
Thu Apr 7 07:04:47 EDT 2016


[Addendum:] We note incidentally that, since Playfair is a substitution, 
it is generally profitable, if desired, to combine the
scheme with transpositions, e.g. the common columnar transposition or
preferrably its variant of the RS44-type, as pre-prosessing and/or
post-processing.

(An RS44-type of transposition can be conveniently specified either via
the matrix of a certain crossword puzzle in a newspaper or journal or
via filling a matrix with a certain natural language sentence and
choosing to have the locations of certain alphabetical characters as
black squares such that there would roughly be a certain desired
percentage of rather randomly distributed squares of the matrix that
are black.)

M. K. Shen


More information about the cryptography mailing list