The Simple Mathematics of Cryptology

PLC XOZ OVM QLI LDV PBB IPI FHB FQF PDL FKD QLY BYL QEC RKX KAB XPV. Oops! I'm getting ahead of myself. We'll get back to this sentence in a very short time, but first, lets discuss what roles mathematics plays in cryptology. The simplest type of cipher is the monoalphabetic substitution cipher (Lewand 1). As its name suggests, this enciphering scheme is based on the idea of replacing each character of a message (the …

…report or a romantic novel. As we work here with a statistical regularity, the more extensive the available text material, the smaller the deviation. Once one realizes which sign stands for e, one can work one's way further into the cipher alphabet. By far the most frequently paired letters in English are th, followed by he, an, in, er. The letters that follow e are, in order of frequency, r, s, n, and d (Kippenhahn 89).