dataexp

I wonder is there is some restricted kind of homomorphic encryption so that the encryption is tailored to be used for certain kind of programs. For example if the program is to compute the average of a list of numbers then some simple encryption could be done just to compute the average and nothing more. Is there some related concept to this idea of the encryption restricted to a concrete computation?

Perhaps it would be easy to code a pseudo trading sequence given a model of the psychological state of the agents in the trading system