Only for hobby I made some ciphers, it is not my intention to use them in the real world but I am trying to compare them with existing ciphers.
An important function of my ciphers is a key stretching function with the following properties:
Kn = increase(Kn-1) where Kn is totaly different from Kn-1 and the length of Kn is 23 - 26 % longer then Kn-1.
The opposite is of course Kn-1 = decrease(Kn).
And the increase function is infinite.
I have been looking for an existing function with these properties for some time but have not found anything yet, i also cannot imagine that something like this is not already in use somewhere.
Is there a function with these or similar properties?
