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The MetaData Service Distributing trust in AAI confederations. Manuela Stanica, DFN. Outline. What is the MetaData Service (MDS)? Role of a MetaData Service in AAI confederations Use of the MDS in eduGAIN The MDS URLs Publishing and retrieving metadata Trust and security considerations
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The MetaData ServiceDistributing trust in AAI confederations Manuela Stanica, DFN
Outline • What is the MetaData Service (MDS)? • Role of a MetaData Service in AAI confederations • Use of the MDS in eduGAIN • The MDS URLs • Publishing and retrieving metadata • Trust and security considerations • Conclusions
What is the MetaData Service (MDS)? • eduGAIN component developed in GN2-JRA5 • eduGAIN: the GÉANT2 AAI • Support dynamic establishment of trust relations between members of AAI confederation • Information model conform to SAML v 2.0 Metadata Specification • SAML: Security Assertions Markup Language (OASIS)
Outline • What is the MetaData Service (MDS)? • Role of a MetaData Service in AAI confederations • Use of the MDS in eduGAIN • The MDS URLs • Publishing and retrieving metadata • Trust and security considerations • Conclusions
AAI confederation hierarchy • AAI confederation interconnecting AAI federations • AAI federation participant institutions users • access to external resources & services • unaware of participants in other federations • require procedure of trust establishment between them
Role of metadata • Connecting to entities in other federated AAIs – required information: • where (in which federation)? • how to reach ? • what is supported (protocols and functionalities)? metadata • distribution to all confederation members • static (pre-configured upon software installation) • dynamic (on request)
Role of a MetaData Servicein AAI confederations • AAI confederations • non-static environments! • frequent updates means for dynamic collection & distribution of metadata: MetaData Service (MDS)
Outline • What is the MetaData Service (MDS)? • Role of a MetaData Service in AAI confederations • Use of the MDS in eduGAIN • The MDS URLs • Publishing and retrieving metadata • Trust and security considerations • Conclusions
Basic principles • Centralised storage of metadata for eduGAIN components • Dynamic retrieval & update • metadata exchange interface: eduGAINMeta • based on REST architecture model • Distributed publishing & querying • among local federations – no central admin • multiple metadata publishers and consumers
Bridging Elements • MDS used by Bridging Elements (BEs): • gateways eduGAIN –local federations • communication with peers (BEs) in other federations • query MDS for metadata about Home BE • MDS response: SAML 2.0 Metadata doc • consumers/publishersof metadata
Outline • What is the MetaData Service (MDS)? • Role of a MetaData Service in AAI confederations • Use of the MDS in eduGAIN • The MDS URLs • Publishing and retrieving metadata • Trust and security considerations • Conclusions
URL structure • Syntax of REST URL mapping: MDS base URL[/federation ID][/entity ID][?query string] • Combinations of: • MDS base URL: https://mds.geant2.net/ • federation ID: dfn, feide,... • entity ID: be1 • query string –Home Locator(s): homeDomain=uio.no
Home Locators • eduGAIN specific atribute-value pairs • For: locating a remote BE (Home BE) • From: • hints provided by user • contents of certificate extensions • Types: • Home domain (homeDomain=switch.ch) • URN (urn=urn:geant:edugain:component:be:switch:be1)
Outline • What is the MetaData Service (MDS)? • Role of a MetaData Service in AAI confederations • Use of the MDS in eduGAIN • The MDS URLs • Publishing and retrieving metadata • Trust and security considerations • Conclusions
Publishing/ updating • Who: metadata publishers • Federation Peering Point (FPP) • authorized Bridging Elements (BEs) • What: SAML 2.0 Metadata documents • EntityDescriptor root ( one BE) • EntitiesDescriptor root ( several BEs) • How: HTTP POST/PUT
Publishing/ updating (2) • For whole federation: • only by FPP • EntitiesDescriptor • URL syntax: <MDS base URL/federation ID> http://mds.ladok.umu.se/feide • For single entities: • by FPP / authorized BEs • EntityDescriptor • URL syntax: <MDS base URL/federation ID/entity ID> http://mds.ladok.umu.se/switch/be1
Retrieving metadata • BE queries MDS via HTTP GET • Metadata lookup • entity/federation name is known • <MDS base URL[/federation ID][/entity ID]> http://mds.ladok.umu.se http://mds.ladok.umu.se/switch http://mds.ladok.umu.se/switch/entity1 • Metadata search • entity name unknown, home locators • <MDS base URL[/federation ID]?query string> http://mds.ladok.umu.se/?homeDomain=switch.ch
Outline • What is the MetaData Service (MDS)? • Role of a MetaData Service in AAI confederations • Use of the MDS in eduGAIN • The MDS URLs • Publishing and retrieving metadata • Trust and security considerations • Conclusions
Trust establishment • Elements of trust establishment in eduGAIN: • MDS • eduGAIN PKI • Component identifiers (CIDs) • MDS trust tightly bound with eduGAIN PKI minimal trust in the service itself • Transitive trust
Security checks • MDS validations: • publisher‘s X.509 certificate • publishing rights • Publishers‘ signatures fwd with metadata validation by consumers
Outline • What is the MetaData Service (MDS)? • Role of a MetaData Service in AAI confederations • Use of the MDS in eduGAIN • The MDS URLs • Publishing and retrieving metadata • Trust and security considerations • Conclusions
Conclusions • MDS: dynamic metadata distribution in AAI confederations • Centralised storage, distributed trust • Employes standard SAML 2.0 Metadata • Possible use in any SAML-based infrastructure • Deployment together with eduGAIN-like PKI