1. A system for limiting reproduction of an electrically representable process comprising: process means for storing symbols U representative of a series of operations performable by a plurality of electrical signals U'; symbol generating and storage means for generating and storing a plurality of test symbols V representative of a go/no-go test and performable by a plurality of signals V'; storage means responsive to said process means and said symbol generating and storage means for storing a composite W of symbols U and V; first translation and memory means for translating said symbols W, stored by said storage means into digitally encoded electrical signals W', including signals U' and V', representative of symbols U and V, respectively, and storing these signals; key generating means comprising means responsive to symbols having, in part, a common derivative to that of said test symbols V for generating key symbols K; second translation and memory means for translating symbols K, from said key generating means, into electrical signals K' and storing same; signal processing means responsive to the receipt of said signals U' for the performance of said series of operations; coupling means responsive to a selected input signal for coupling said signals U' from said first translation and memory means to said signal processing means; and a process limiting means comprising: correlation means including means for effecting a selected correlation between aspects of said signals V', from said first translation and memory means, and signals K', from said second translation and memory means, and for providing a correlation output signal which is a function of said correlation; and signal means responsive to a selected output of said correlation means for providing an input signal to said coupling means; whereby, upon said selected output of said correlation means, the performance of said series of operations is enabled.