AAF Validator Service
AAF Core Attributes

Number of values
A scoped identifier for a person. It should be represented in the form "user@scope" where 'user' is a name-based identifier for the person and where 'scope' defines a local security domain. Each value of 'scope' defines a namespace within which the assigned identifiers MUST be unique. Given this rule, if two eduPersonPrincipalName (ePPN) values are the same at a given point in time, they refer to the same person.

Syntactically, ePPN looks like an email address but is not intended to be a person's published email address or be used as an email address. In general, name-based identifiers tend to be subject to some degree of expected change and/or reassignment.

Notes on usage
Values of eduPersonPrincipalName are often, but not required to be, human-friendly, and may change as a result of various business processes. They may also be reassigned after a locally-defined period of dormancy. Applications that require a guarantee of non-reassignment and more stability, but can tolerate values unfriendly (and unknown) to humans should refer to the eduPersonTargetedID attribute.