All parties associated with secure computation in SDM are known via
principals: identities (unique names) that can be
authenticated. We further restrict attention to scoped
principals, for example Syracuse's Nataraj, where the scope
represents an organizational domain (which may in turn be further
structured and scoped in any fashion). Principals are most often
associated with individual people. However, they may also be
associated with entities such as departments (as in Acme's
MarketingDept, entire companies, or any other authenticatable unit.
In SDM, we further categorize principals in terms of the properties
and usages as discussed in the remainder of this paper and
implemented via the classes and interfaces illustrated in Figure
.