Specification and System Parameters

The description of interface events in Section 5.2.4 contained several free variables, mostly denoting sets used as domains for parameters. This section discusses how these variables are bound. All the sets must be coimtable and non-empty, and for some of them, a restriction of the values they can assume is already known. Here is the complete list of them with some new restrictions. 

This set of strings is the first formal notion that deals with transactions. 

As long as a variable v such as those described above is free, it defines a family of 

One could even define that MessageJjounds is either ) or M itself, i.e., either no input N is needed or any number is possible. All known signature schemes have a variant that works for one of these cases. However, it is simpler if one can, for instance, restrict MessageJjounds to powers of 2 in schemes with tree authentication. 

Instead, one could also fix v once and for all, e.g., one could define that the message space of all signature schemes were the set of all bit strings. As the opposite extreme, one could make V an input parameter, e.g., in initialization or in a global transaction at the system start. But in both cases, that should have been done in Section 5.2.4 already. 

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