http://data.europa.eu/2sa/elap/security-design
Security by design refers to one of the prime principles found in any standard and in any practice throughout the whole of IT.
Rationale
Security by design encompasses the protection of valuable assets, by securing them safely within the boundaries of organizations, taking into account the ownership of the assets. This means that in any circumstance, one has to attend to the valuable property, being 'data' and 'technology' as a whole, both by securing access to (data)assets and by securing the proliferation of data(assets) outside the boundaries, for which one is responsible.
Security by design (or secure by design), sometimes abbreviated �SbD,� is a new industry term for a range of security practices built on one fundamental idea � that security should be built into a product by design, instead of being added on later by third-party products and services.
Principle Source
Security and Privacy Underlying Principle (8) of the European Interoperability Framework (EIF)