This licentiate thesis consist of two separate research papers which concern two tangential topics – that of semantic information and that of information security. Both topics are approached by similar methods, i.e. with a concern about conceptual and definitional issues. In Paper I – concerning the concept of information, and a semantic conception thereof – the conceptual, and definitional, issues focus on one property, that of truthfulness. It is argued – against the veridicality thesis – that semantic information need not be truthful. In Paper II – concerning information security – it is argued that the current leading definitions (so-called ‘CIA’ definitions, which define information as secure if, and only if, the properties of confiden...