Cryptography and Multiple layer encryption

[Drache]

I've been thinking about a new type of encryption, really an older type of encryption, but with a twist. Standard public key systems are fairly secure, but one of the ways to break them is to brute force the private key, either the pass phrase or the number itself. This would be impossible if a two layer key system was established. It would have to be set up so that key one generates coded output based only on the key it recieves first. This new coded output would then be decoded to plain text with the next key. Obviously then, the bruteforcing algorithem would not detect any plain text, even if it succesfully cracked the first phrase, so the message could never be decoded without both pass phrases.
Any ideas on this/how to implement this?

[YT2095]

it sounds like a variation of the old "one time" books used during the war, only difference is that it would be on a "local" basis and use an input determined rolling code, they`re difficult, but not impossible to crack as long as it`s based on an algorithm, it has LOGIC, and where there`s Logic, there will be a "key" :)

[Drache]

Forgot to mention, it would be public key based, so double layer PGP