Method for processing data, in which a Petri net is encoded, written into a memory and read and executed by at least one instance, wherein transitions of the Petri net read from at least one tape and/or write on at least one tape symbols or symbol strings, with the aid of at least one head. [FIG. 1]. In an alternative, data-processing, co-operating nets are composed, the composition result is encoded, written into a memory and read and executed from the memory by at least one instance. In doing this, components can have cryptological functions. The data-processing nets can receive and process second data from a cryptological function which is executed in a protected manner. The invention enables processing of data which prevents semantic analysis of laid-open, possibly few processing steps and which can produce a linkage of the processing steps with a hardware which is difficult to isolate.