Security protocols for secret Santa

The motivation for the current report lies in a number of questions concerning the current state of the art in security protocol design and analysis. Why is it so hard to develop a complete set of security requirements for a particular problem? For instance, even in the seemingly simple case of defining the secrecy property of an encryption algorithm it has taken decades to reach a degree of consensus, and even now new definitions are required in specific contexts. Similarly, even after more than twenty years of research on e-voting, there is still a lack of consensus as to which properties an e-voting protocol should satisfy. What did we learn from this research experience on e-voting? Can we apply the knowledge accumulated in this domain to similar domains and problems? Is there a methodology underlying the process of understanding a security protocol domain?