Considered are the main factors affecting the reliability and safety of the operation of the software products in realtime, characteristics of systems and environment for which must be ensured by their functional safety and the required resources. Outlines the requirements to the design of the functional suitability of the complex programs, organization, planning and development processes of the requirements to the security of software products. The major international standards of technological processes, ensuring functional security in a life cycle of complex software systems are described. Considerable attention is focused on testing of functional security of software products.