The best algorythm so far to use in cryptography is the secure hashin function. You have seen it as SHA256 or secure hashing algorithm and the number 256 means the bit of information you can use for the encryption process. The math behind allows you to encypt something and then make it impossible to decrypt. Of course you can use Furier equations as well as Fibbonaci numbers in your encryting algorithm but that will never be so secure as SHA256.