The paper offers a solution to the problem of specifying computational systems that behave in accordance with a given set of ethical principles. The proposed solution is based on the concepts of ethical requirements and ethical protocols. A new conceptual tool, called the Control Closure of an operation, is defined and used to translate ethical principles into ethical requirements and protocols. The concept of Generalised Informational Privacy (GIP) is used as a paradigmatic example of an ethical principle. GIP is defined (...) in such a way as to (i) discriminate specific cases in which an individual’s GIP can be infringed without accessing the individual’s data; (ii) separate unauthorised accesses to data that do not respect the right to GIP from access that do; and (iii) distinguish different degrees of GIP. Finally a camera phone is used to illustrate the proposed solution. (shrink)