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 plaintext message) with a unique alternate character to obtain an encryption (the ciphertext message). …