Add in functionality for poly-alphabetic substitution cipher, aka Vigenere cipher.
Similar to mono-alphabetic cipher, but instead of 1 alphabet key used to perform the substitution, there are multiple. First letter of plaintext is enciphered using the first key, second letter uses the second key, etc. When all keys have been used once, go back to the first key again and loop through as many times as necessary.
Prompt user to enter number of alphabet keys, then prompt user to enter them 1 by 1.
Add in functionality for poly-alphabetic substitution cipher, aka Vigenere cipher. Similar to mono-alphabetic cipher, but instead of 1 alphabet key used to perform the substitution, there are multiple. First letter of plaintext is enciphered using the first key, second letter uses the second key, etc. When all keys have been used once, go back to the first key again and loop through as many times as necessary. Prompt user to enter number of alphabet keys, then prompt user to enter them 1 by 1.