Model-based development of security requirements

We present a model-based approach using two dimensions to propagate security restrictions: along the lifecycle and along the architectural levels. We apply security patterns to perform this propagation. We believe that this double propagation can be very effective for security and reliability. This approach can also facilitate the security analysis of the system and can be used to verify compliance with regulations. We have developed a methodology to apply these ideas and we are extending it to make it more powerful, in particular to increase its level of security and to add to it also reliability concerns. The extensions include two new metamodels for security requirements and a validation approach.