Polyalphabetic substitution ciphers, from which the first one was Alberti cipher, were an advancement over monoalphabetic substitution ciphers simply because of their use of multiple alphabets in the encipherment process. Each one that followed the Alberti cipher tried to improve a vulnerability that the previous one possessed. The Trithemius cipher used a different alphabet for every letter that it processed, the Vigen`ere cipher didn’t have linear movement over the so-called tabula recta, while the Beaufort cipher is considered to be a variant of the Vigen`ere cipher. Furthermore, the Playfair cipher had a new perspective of the encipherment problem using bigrams and 5×5 letter matrix. The four-square cipher can be considered as an extension of the Playfair cipher with improved security because it applies a similar logic to four such matrices, while the two-square cipher attempts to obtain the best of these two cryptosystems – better text encryption then the Playfair cipher while being easier to use then the four-square cipher. Finally, a completely new perspective on the encipherment problem was provided by Hill’s cipher based on linear algebra.