🚀 go-pugleaf

In article <92207.142318U27239@uicvm.uic.edu> U27239@uicvm.uic.edu (Gerald Strom) writes:
>This Caesar Cipher is not secure by the standards of today but
>interestingly, the method used, substituting one letter or character for
>another in a regular way, is still the fundamental basis for encipherment
>in modern ciphers systems.  The DES system developed by the United States
>government, the various public key ciphers systems, as well as the German
>Enigma cipher cracked by Allen Turing during World War II using one of the
>first computers are all substitution ciphers whereby letters in the plain
>(or un-enciphered) text are replaced by different letters or characters to
>create the cipher (or enciphered) text.

This is an inaccurate statement.  It gives the impression that all these
systems operate on individual characters and are as insecure as Caesar.

A transposition over, say, 25-byte blocks is a substitution just as DES is
a substitution over 8-byte blocks -- only the transposition is simpler.

A one time pad is a substitution cipher -- and about as secure as you can
get.

A self-inverse transposition was posted here a month or two ago --
operating over large blocks (up to 8K).  With FFT techniques, we can build
a much larger block DES -- eg., operating on 8K blocks.  I would prefer
the large DES over a large transposition.