XDI Graph Patterns OASIS XDI TC Submission Drummond Reed, Markus Sabadello This summary document contains XDI introductory materials. The long form includes illustrations of many standard XDI graph patterns: 1.XDI references: XDI statements used to assert multiple XDI identifiers for the same logical resource 2.Peer graphs and XDI discovery: statements used to describe and navigate the distributed global XDI graph 3.Social graphs: relationships between XDI authorities 4.Attribute singletons: contexts that contain a single literal value 5.Attribute class/instance collections: contexts that contain an ordered or unordered set of attribute instances 6.Entity singletons: contexts that represent a single entity 7.Entity class/instance collections: contexts that contain an ordered or unordered set of entity instances 8.Personas and roles: entities and relations that model contextual identity for individuals 9.Outer and inner roots: a graph-within-a-graph 10.Link contracts: contexts and relations used for XDI authorization 11.Policy expression: conditional logic for rules evaluation 12.Messages: XDI graphs used in the XDI protocol 13.Dictionaries: machine-readable XDI ontology definitions 1

XDI Graph Model (Short Form) 2 Node Attribute ContextLiteral GraphSubgraph EntityValue Variable

XDI Graph Model (Long Form) 3 Node Attribute ContextLiteral GraphSubgraph EntityValue & Definition | | SingletonCollection [ ] MemberDefinition | | SingletonCollection [ ] Member CommonPeer ( ) Inner ( / ) Variable { } Ordered Unordered Unordered ! AuthorityClass Personal = Legal + General * Reserved $ Unreserved # AuthorityClass Personal Legal General Reserved Unreserved

XDI context symbols Identifier for a legal entity that is not required to be a natural person Specific keywords for XDI grammar Generic classes Identifier for a natural person 4 SymbolSemanticsExamples = + # $ Context Personal Legal Unreserved Reserved +neustar +kynetx $and $or #photo # =markus =drummond.reed Authorities A member of an unordered set of instances (immutable) SymbolSemanticsExamples ! Context Unordered!1234 !4c3f.87e2 Members SymbolSemanticsExamplesContext Classes A member of an ordered set of Identifier for an entity that is not required to be a legal entity * General *daisy *back.forty

XDI function syntax Identifies a variable used in queries and templates Identifies the root node of an entire XDI graph 5 BracketsSemantics ( ) { } Function Graph Variable Graph Functions Identifies an XDI attribute that may have a literal value Identifies a collection of XDI entities or attributes BracketsSemantics [ ] Function Collection Attribute Context Functions These functions may contain multiple XDI contexts and/or an XDI relation These functions may only contain a single XDI context Identifies the definition of an XDI entity or attribute | Definition

XDI Graph Notation Entity context node: A subgraph (branch) of the graph that may contain entity or attribute context nodes Contextual arc: Uniquely identifies a context node Relational arc: Non-uniquely links context nodes Literal node: Optional child node of a value node containing a literal data value (any valid JSON value) Root context node: The starting point of an XDI graph that may contain root, entity, or attribute context nodes Literal arc: Singleton arc to a literal node 6 SymbolUsage Value context node: A leaf (terminal) node of the context graph that may contain zero or one literal node Attribute context node: A subgraph (branch) of the graph that may contain attribute or value context nodes 1 Singleton n Collection x Member SingletonCollectionMember 1 nx “value”

7 “ ” [ ] “ T11:12:13Z” $ref =alice “ e2-bcfd c0002)” & & Example XDI graph “ & ([=]!:uuid:f81d4fae-7dec-11d0-a765-00a0c91e0001) $ref & !:uuid:f81d4fae-7dec-11d0-a765-00a0c91e0001 [=] ([=]!:uuid:9ce739f e2-bcfd c0002) !:uuid:9ce739f e2-bcfd c0002 =bob $ref +friend