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- (Unique-1) The user identifier represents a single natural person;
- (Unique-2) The Identity Provider can contact the person to whom the identifier is issued;
- (Unique-3) The user identifier is never re-assigned; and
- (Unique-4) The user identifier is eduPersonUniqueId (if used), SAML 2.0 persistent name identifier, SAML 2.0 Subject Identifier Attribute subject-id or SAML 2.0 Subject Identifier Attribute pairwise-id.
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