An example is a DNA based computer, where many different cells are working on the same problem at any given time. The reader is challenged to invent other models and check the following analysis. This reservoir will be the set of all keys and energies available to the cipher function and will become our the basis for our blind. That is we know that , and is an exponential funcion so we can work with ln . Let us also agree to drop the superscripts because, henceforth, they have no meaning.
All roads lead to Rome.
Just as an empire that dominated the world required the Romans to construct a set of roads wich led back to a single, fortified, source, a cipher blind that thwarts thermodynamic attacks must construct a blind in which all avenues of attack lead to a single, and hence meaningless, answer. A blinding function requires that all thermodynamic measurements of a cipher process return the same answer. Equivalently, it demands that the most probable keys be identical across all cipher functions. Given a space of all possible ciphers the most naturally identified single point in that space is the central point. This amounts to the requirement that the central point lies in the middle of a shpere who's radius we define by setting all state probabilities equal.