Is this a bad idea?

Question

I am working on devising a theortecially unbreakable code..so i compiled 3 codes into one, one is the Vigenere's cipher, the other is the Play fair Cipher, and the other is the four squares cipher. Is it a bad idea to put so many different ciphers together? Or is it going to ensure maximum security?

Answer 1

Combining cyphers can increase security because the original plain text is not random, and the lack of randomness can be exploited to crack the code. By enciphering with one cipher after another, the non randomness is increasingly concealed.

Off hand I don't know of the four squares cipher, but the other two can be attacked by looking at pairs of letters.

There is a difference between hard to break and unbreakable.

The only unbreakable code discovered so far is the one time pad. You need a source of genuinely random numbers to create the pad. Any non randomness spoils it.

The difficulty in use is in distributing the key to both sender and receiver. It must be as long as the message, and can never be reused. So a lot of key must be sent securely.

Answer 2

YES.