The statement "What You See Is What You Sign" (WYSIWYS) expresses a functional requirement for digital signatures of electronic documents, in particular when considering legally binding signatures. However this statement is intrinsically wrong. In fact a signer never really sees what he digitally signs, namely the bits of the electronic document, but he sees only one of the possible representations of these bits. This is due to the theory and the technology underlying the actual implementations of the digital signatures. Moreover, while the acronym refers only to the presentation on the signer side, in legal settings the presentation on the recipient side must be also taken into account as well as the relation between the twos. The current status of research in this field can be summarized as follows. Many different definitions of WYSIWYS can be found and sometime this requirement is described only through some of its supposed effects. Therefore a clear and unambiguous definition of WYSIWYS is still missing. Conversely many security threats related to the document presentation have been described. In addition some theoretical and practical solutions have been proposed to design applications capable to properly present the electronic documents. Anyway many proposals take into account only a subset of the problems to be solved while others guarantee a correct presentation at the price of compromising their usability. We think this is the current situation first because the exact requirements for the document presentation on both the signer and the verifier side have not been clearly identified. Then because of the lack of a theoretical and comprehensive model to deal with these requirements. In this short paper we intend to show one of the possible directions the research in this field could move towards.
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