SUBSTITUTION CIPHER WITH PSEUDO-RANDOM SHUFFLING: THE DYNAMIC SUBSTITUTION COMBINER
Terry Ritter · Cryptologia · 1990
A cipher mechanism or process which can be viewed as a modified substitution cipher. A translation table is used to replace plaintext symbols with ciphertext symbols; the modification consists of changing the contents of the translation table after each substitution. The dynamic translation table acts to confuse symbol frequency statistics and so frustrate the usual cryptanalytic attacks. The same mechanism can also be viewed as a cryptographic combiner, and can replace the exclusive-OR combining function used in Vernam stream ciphers. The dynamic translation table acts as one-way function to protect the pseudo-random sequence, and consequently helps to prevent cryptanalysis.