Da intercepção de comunicações, acções encobertas e serviços de informações

The Portuguese Intelligence Services have their operational skills limited due to the grievances caused by the Dictatorship and, in particular, by its political police. With the help of historical elements, and by analyzing current legislation, we demonstrate that such grievances are today unjustified and misplaced, mainly taking into account the Risk Society’s multifaceted threats. Also part of our analysis is the impugnment of the Constitutional Court’s decision nº 413/2015, which pronounced unconstitutional the norm contained in Decree nº 426/XII, of the Republic’s Assembly, article nº 78, nº2, which intended to allow Intelligence Services access to the so-called “metadata”, as well as to tax and banking information. It is our understanding, and we demonstrate it in our dissertation, that should be allowed the access of, not only the above mentioned information, but also the means known as communications interception and undercover operations to the Intelligence Services, as long as properly supervised and inspected.

A type system for value-dependent information flow analysis

Information systems are widespread and used by anyone with computing devices as well as corporations and governments. It is often the case that security leaks are introduced during the development of an application. Reasons for these security bugs are multiple but among them one can easily identify that it is very hard to define and enforce relevant security policies in modern software. This is because modern applications often rely on container sharing and multi-tenancy where, for instance, data can be stored in the same physical space but is logically mapped into different security compartments or data structures. In turn, these security compartments, to which data is classified into in security policies, can also be dynamic and depend on runtime data. In this thesis we introduce and develop the novel notion of dependent information flow types, and focus on the problem of ensuring data confidentiality in data-centric software. Dependent information flow types fit within the standard framework of dependent type theory, but, unlike usual dependent types, crucially allow the security level of a type, rather than just the structural data type itself, to depend on runtime values. Our dependent function and dependent sum information flow types provide a direct, natural and elegant way to express and enforce fine grained security policies on programs. Namely programs that manipulate structured data types in which the security level of a structure field may depend on values dynamically stored in other fields The main contribution of this work is an efficient analysis that allows programmers to verify, during the development phase, whether programs have information leaks, that is, it verifies whether programs protect the confidentiality of the information they manipulate. As such, we also implemented a prototype typechecker that can be found at http://ctp.di.fct.unl.pt/DIFTprototype/.