The present invention provides methods and apparatuses for implementing communications privacy on a class of two-way wireless control communications. The methods and apparatuses of the present invention are cryptographic in nature and are built on a symmetric cryptographic algorithm structure. The cryptographic algorithm structure generates keytext on a frame-by-frame basis and both directions of the communications control link are served by the same keytext frames. The methods and apparatuses of the present invention utilize a single outbound/inbound cryptographic generator, such as a shrinking generator or the like designed using six-sigma tools in order to ensure, within a predetermined probability, that the non-fixed encryption time does not cause operational problems.