Pervasive digital signatures: Syntactic robustness and simplicity of signed documents

The action of digitally signing has several intrinsic weaknesses that introduce syntactic and semantic distance between a signer and a relying party. As a result, digitally signed documents cannot be trusted and thus be widely deployed in pervasive environments. We evaluate the syntactic robustness of digitally signed documents by exploiting one key quantitative measure (the structural informativeness) and by comparing several qualitative characteristics of various alternative syntaxes. We are then able to identify which is the more reliable and simpler to transform syntax that will enhance the pervasiveness of signed documents, while it can be used in resource-constraint mobile devices. At the same time, digitally signed documents must preserve their security characteristics and their formatting and layout capabilities in order to achieve an enhanced level of trust on the semantic part of communication and thus be ubiquitously integrated with human users.