Liberty Glossary v2.0


Jeff Hodges, NeuStar, Inc.


Robert Aarts, TrustGenix
Carolina Canales-Valenzuela, Ericsson
Peter Davis, NeuStar, Inc.
John Kemp, Nokia
Elisa Korentayer, IEEE-ISTO
John Linn, RSA Security, Inc.
Paul Madsen, NTT
Rob Lockhart, IEEE-ISTO
Thomas Wason, IEEE-ISTO


This document has been prepared by Sponsors of the Liberty Alliance. Permission is hereby granted to use the document solely for the purpose of implementing the Specification. No rights are granted to prepare derivative works of this Specification. Entities seeking permission to reproduce portions of this document for other uses must contact the Liberty Alliance to determine whether an appropriate license for such use is available. Implementation of certain elements of this document may require licenses under third party intellectual property rights, including without limitation, patent rights. The Sponsors of and any other contributors to the Specification are not and shall not be held responsible in any manner for identifying or failing to identify any or all such third party intellectual property rights.

This Specification is provided “AS IS”, and no participant in the Liberty Alliance makes any warranty of any kind, express or implied, including any implied warranties of merchantability, non-infringement of third party intellectual property rights, and fitness for a particular purpose.

Implementers of this Specification are advised to review the Liberty Alliance Project’s website ( for information concerning any Necessary Claims Disclosure Notices that have been received by the Liberty Alliance Management Board.

Copyright © 2006 Adobe Systems; America Online, Inc.; American Express Company; Amsoft Systems Pvt Ltd.; Avatier Corporation; Axalto; Bank of America Corporation; BIPAC; BMC Software, Inc.; Computer Associates International, Inc.; DataPower Technology, Inc.; Diversinet Corp.; Enosis Group LLC; Entrust, Inc.; Epok, Inc.; Ericsson; Fidelity Investments; Forum Systems, Inc.; France Télécom; French Government Agence pour le développement de l’administration électronique (ADAE); Gamefederation; Gemplus; General Motors; Giesecke & Devrient GmbH; GSA Office of Governmentwide Policy; Hewlett-Packard Company; IBM Corporation; Intel Corporation; Intuit Inc.; Kantega; Kayak Interactive; MasterCard International; Mobile Telephone Networks (Pty) Ltd; NEC Corporation; Netegrity, Inc.; NeuStar, Inc.; Nippon Telegraph and Telephone Corporation; Nokia Corporation; Novell, Inc.; NTT DoCoMo, Inc.; OpenNetwork; Oracle Corporation; Ping Identity Corporation; Reactivity Inc.; Royal Mail Group plc; RSA Security Inc.; SAP AG; Senforce; Sharp Laboratories of America; Sigaba; SmartTrust; Sony Corporation; Sun Microsystems, Inc.; Supremacy Financial Corporation; Symlabs, Inc.; Telecom Italia S.p.A.; Telefónica Móviles, S.A.; Trusted Network Technologies; UTI; VeriSign, Inc.; Vodafone Group Plc.; Wave Systems Corp. All rights reserved.

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This glossary defines many of the technical terms and phrases used in Liberty Alliance Project specifications and documents.

Table of Contents

1. Introduction
2. Definitions

1. Introduction

This document is the Liberty Alliance Project glossary of normative technical terms.

This document is not an exhaustive compendium of all Liberty technical terminology because the Liberty terminology is built upon existing terminology. Thus many terms that are commonly used within this context are not listed. They may be found in the glossaries/documents/specifications referenced in the bibliography. Terms defined here that are not attributed to other glossaries/documents/specifications are being defined here.

This glossary is expected to evolve along with the Liberty Alliance Project specifications.

2. Definitions



See authentication context.

abstract WSDL

An abstract WSDL service definition is that portion of a WSDL document [WSDLv1.1] — describing said service — comprised of the <wsdl:types>, <wsdl:message>, and <wsdl:portType> elements.


A formal business agreement providing for regular dealings and services between a Principal and a service provider [Merriam-Webster].

account linkage

See identity federation.


See Authentication Domain.


An affiliation is a set of one or more entities, described by providerID’s, who may perform Liberty interactions as a member of the set. An affiliation is referenced by exactly one affiliationID, and is administered by exactly one entity identified by their providerID. Members of an affiliation may invoke services either as a member of the affiliation (using affiliationID), or individually (using their providerID). Affiliation and affiliation group are equivalent terms.

affiliation group

See affiliation.

Affiliation ID

An Affiliation ID identifies an affiliation. It is schematically represented by the affiliationID attribute of the <AffiliationDescriptor> metadata element [LibertyMetadata].


See Attribute Provider.

AS Consumer

See Authentication Service Consumer.

AS Provider

See Authentication Service Provider.

assertion, SAML assertion

An XML-based data structure defined by SAML. Assertions are collections of one or more statements, made by a SAML authority (also known as an issuer), such as an authentication statement or attribute statement. As used in Liberty, assertions typically concern things such as: an act of authentication performed by a Principal, attribute information about a Principal, or authorization permissions applying to a Principal with respect to a specified resource.


A distinct, named, characteristic of a Principal or other system entity.

attribute class

A predefined set of attributes, such as the constituents of a Principal’s name (prefix, first name, middle name, last name, and suffix).

attribute container

A module comprised of a collection of attributes grouped together according to expected use patterns.

Attribute Provider (AP)

An attribute provider (AP) provides Identity Personal Profile (ID-PP) information. Sometimes referred to as an ID-PP provider.

authenticated identity

An identity, representing a system entity, which often is a Principal, that is asserted to have been the subject of a successful authentication.

authenticated Principal

A Principal who has had his identity authenticated by an Identity Provider.

authenticating authority

Synonymous with authenticating identity provider or authenticating IdP. An identity provider that authenticated a Principal (see also authentication). In [LibertyAuthnContext], the authenticating authority is identified by the first occurring <AuthenticatingAuthority> element instance.

authenticating entity

system entity that engages in the process of authenticating itself to another system entity, the latter typically being an Identity Provider (see also authentication). More formally, an authenticating system entity.

authentication (authn)

Authentication is the process of confirming a system entity‘s asserted identity with a specified, or understood, level of confidence [TrustInCyberspace].

authentication assertion

A SAML-based assertion that, in the Liberty specification suite, contains a <lib:AuthenticationStatement>. Note that the foregoing element is defined in a Liberty namespace. Also known as Liberty authentication assertion and ID-FF authentication assertion.

Liberty authentication assertions are formal XML extensions of SAML assertions [SAMLCore11].

Semantically, an assertion issuer is stating that the subject of the assertion authenticated with it (the issuer) at some point in time. Assertions are typically time-limited.

authentication authority

system entity that produces authentication assertions [SAMLGloss2]. In the Liberty architecture, it is typically an Identity Provider.

authentication context (AC)

Authentication Context is an extensible XML-based “schematic” description of authentication event characteristics [LibertyAuthnContext].

Authentication Domain (AD)

An Authentication Domain (AD) is a formal community of Liberty-enabled entities that interact using a set of well-known common rules.

authentication exchange

See authentication protocol exchange.

authentication mechanism

An authentication mechanism is a particular, identifiable, process or technique that results in a confirmation of a system entity‘s asserted identity with a specified, or understood, level of confidence. See also SASL mechanism. An authentication mechanism may be employed in the process of generating security tokens attesting to the authenticated identity of an authenticating entity. The ID-WSF Authentication Protocol specifies such a process [LibertyAuthn].

authentication protocol exchange

Authentication protocol exchange is the term used in [RFC4422] to refer to the sequence of messages exchanged between the client and server as specified and governed by the particular SASL mechanism being employed to effect an act of authentication.

authentication quality

The level of assurance that a service provider can place in an authentication assertion it receives from an identity provider.

authentication server

The precise, specific role played by a server in the protocol message exchanges defined in the ID-WSF Authentication Protocol.

Authentication Service Consumer (AS Consumer)

Web Service Consumer (WSC) implementing the client-side of the ID-WSF Authentication Service [LibertyAuthn].

Authentication Service Provider (AS Provider)

Web Service Provider (WSP) implementing the server-side of the ID-WSF Authentication Service [LibertyAuthn].

authentication session

The period of time starting after A has authenticated B and until A stops trusting B’s identity assertion and requires reauthentication. Also known simply as a session, it is the state between a successful login and a successful logout by a Principal.

authorization (authz)

The process of determining, by evaluating applicable access control information, whether a subject is allowed to have the specified types of access to a particular resource. Usually, authorization is in the context of authentication. Once a subject is authenticated, it may be authorized to perform different types of access [SAMLGloss2].

bearer token

bearer token is a form of security token having the property of connoting some attribute(s) to its holder, or bearer. In [LibertySecMech], bearer tokens connote identity and they consist essentially of credentials of some form, e.g., SAML assertions [wss-saml11].


See discovery bootstrap.

Circle of Trust (CoT)

A federation of service providers and identity providers that have business relationships based on Liberty architecture and operational agreements and with whom users can transact business in a secure and apparently seamless environment. Also known as a Trust Circle.


role assumed by a system entity who makes a request of another system entity, often termed a server [RFC2828]. A client is at varying times a sender or a receiver.

concrete WSDL

A concrete WSDL document (which includes at least the <wsdl:binding>, <wsdl:service>, and <wsdl:port> elements) that contains the protocol endpoint information necessary for a client to communicate with a particular service instance.


See circle of trust.


Data that is transferred or presented to establish either a claimed identity or the authorizations of a system entity.

defederate, defederate identity

To eliminate linkage between a Principal’s accounts at an identity provider and a service provider.


Enabling a system entity to operate on behalf of a principal to access an identity service.


discoverable “in principle” service is one having an service type URI assigned (this is typically in done in the specification defining the service). A discoverable “in practice” service is one that is registered in some discovery service instance.

ID-WSF services are, by definition, discoverable in principle because such services are assigned a service type URI facilitating their registration in Discovery Service instances. Once so registered, they are discoverable in practice.

discovery bootstrap

A SAML (see [SAMLCore2]) <Attribute> element defined such that an Endpoint Reference (EPR) for the discovery service itself—an ID-WSF EPR—can be conveyed via SAML assertions. Upon authentication or SSO, such a “discovery bootstrap” is conveyed to the authenticating (aka relying) party as a part of the Principal’s security token. The relying party is thus able to query the Principal’s discovery service for references to the Principal’s other identity services.

Discovery Service (DS)

An ID-WSF service facilitating the registration, and subsequent discovery of, ID-WSF service instances [LibertyDisco], as indexed by Principal identity. See also discoverable.

Discovery Service Provider (DS Provider)

Web Service Provider (WSP) implementing the server-side of the ID-WSF Discovery Service [LibertyDisco].


A term used in [WSDLv1.1] — it is the short form of protocol endpoint — and which itself means an identified entity, at the current level of abstraction, to which a protocol message, of the same level of abstraction, may be sent. For example, at the Internet Protocol (IP) layer, an endpoint is represented by an IP address, and one may send an IP datagram (AKA a “message”) to said endpoint. In contrast, at the HTTP layer, an endpoint is represented by a URL, in conjunction perhaps with other information included in the so-called “HTTP header”.

See also ID-WSF Endpoint Reference.


To link or bind two or more entities together.


  1. (1) The act of establishing a relationship between two entities.
  2. (2) An association comprising any number of service providers and identity providers.

final SASL response

The final <SASLResponse> message sent from the server to the client in an authentication exchange [LibertyAuthn].


See generic web service.


See generic Web Service Provider.

generic web service (gWS)

generic web service is defined by sense (1) of the web service definition.

generic Web Service Provider (gWSP)

generic Web Service Provider (gWSP) an entity providing generic web services.

header, header block, header element

See SOAP header block.


A shorthand designator referring to the Liberty ID-WSF, ID-FF, and ID-SIS specification sets. For example, one might say that the former specification sets are all part of the Liberty ID-* specification suite.

ID-* fault message

An ID- fault message is a SOAP [SOAPv1.1] <S:Fault> element containing a <Status> element, with the attributes and attribute values of both elements configured as specified herein, or as specified in other specification(s) in the ID-WSF or ID-SIS specification sets.

ID-* header block

One of the header blocks defined in this specification, or defined in any of the other Liberty ID-* specification suite.

ID-* message

Equivalent to ordinary ID-* message.


The Identity Federation Framework (ID-FF) is the title for a subset of the Liberty specification suite which defines largely HTTP-based protocols for web single sign-on and identity federation [LibertyProtSchema].

ID-FF authentication assertion

See authentication assertion.


The “ID Personal Profile” is an ID-SIS -based service which can provide profile information regarding Principals, typically subject to policy established by said Principals [LibertyIDPP].


Liberty Identity Service Interface specification set.

ID-SIS service

See ID-SIS-based service.

ID-SIS-based service

ID-SIS-based services are identity services typically built on ID-WSF — i.e., they are essentially ID-WSF-based services — and are often also built on the [LibertyDST] specification. [LibertyIDEP] and [LibertyIDPP] are examples of ID-SIS service specifications.


Liberty Identity Web Services Framework specification set.

ID-WSF Endpoint Reference

An ID-WSF Endpoint Reference (ID-WSF EPR) is a reference to a service instance. It contains the address, security context, and other metadata necessary for contacting the identified service instance. The underlying structure of an ID-WSF EPR is based on wsa:EndpointReference [WSAv1.0-SOAP] [WSAv1.0], and conceptually is similar to the Resource Offering from earlier versions of the Discovery Service specification.


See ID-WSF Endpoint Reference.

ID-WSF service

See ID-WSF-based service.

ID-WSF-based service

An ID-WSF-based service is an identity service that is at least discoverable in principle, and is based on [LibertySOAPBinding] and [LibertySecMech].


The essence of an entity. One’s identity is often described by one’s characteristics, among which may be any number of identifiers.

Principal may wield one or more identities. See also Principal identity.

Identity federation

Creating associations between a given system entity’s identifiers or accounts.

Identity Mapping Service (IMS)

An ID-WSF-based service that enables a requester to obtain one or more identity tokens (see identity token). It translates references to a principal into alternative formats or identifier namespaces. This service exposes a generalization of the Name Identifier Mapping protocol defined in [SAMLCore2] [LibertyAuthn].

Identity Provider (IdP)

A Liberty-enabled system entity that manages identity information on behalf of Principals and provides assertions of Principal authentication to other providers.

identity service

See identity web service.

identity token

Identity tokens [LibertySecMech20SAML][LibertySecMech] are a means for conveying the identity of a Principal involved in an ID-WSF interaction, by means of stipulating one of the Principal’s identifiers, as well as (typically) an ID-WSF EPR denoting the Principal’s Discovery Service.

identity web service

A type of web service whose operations are indexed by identity. Such services maintain information about, or on behalf of, Principals — as represented by their identities — and/or perform actions on behalf of Principals. They are also sometimes referred to as simply identity services.

In Liberty ID-WSF, such services are both mapped on a per-principal basis and discoverable — meaning that once a Principal authenticates, the authenticating party possesses a reference to the Principal’s Discovery Service instance, which it may use to discover the Principal’s other identity services. See also “discoverable.”

See also Discovery Servicediscoverableweb service (2), and [LibertyDisco].

initial response

A [RFC4422] term referring to authentication exchange data sent by the client in the initial SASL request. It is used by a subset of SASL mechanisms. See Section 5.1 of [RFC4422].

initial SASL request

The initial <SASLRequest> message sent from the client to the server in an authentication exchange [LibertyAuthn].

Interaction Service (IS)

An ID-WSF service that allows providers to pose simple questions to Principals in order to, for instance, clarify that Principal’s preferences for data sharing, or to supply some needed attribute.


See Identity Provider.

invocation identity

The identity of the system entity invoking a service.


See Liberty-Enabled Client.


See Liberty-Enabled Client or Proxy .


See Liberty-Enabled Proxy.

Liberty authentication assertion

See authentication assertion.

Liberty-enabled client (LEC)

An entity that has, or knows how to obtain, knowledge about the identity provider that the Principal wishes to use with the service provider.

Liberty-enabled client or proxy (LECP)

A Liberty-enabled client is a client that has, or knows how to obtain, knowledge about the identity provider that the Principal wishes to use with the service provider. A Liberty-enabled proxy is an HTTP proxy (typically a WAP gateway) that emulates a Liberty-enabled client.

Liberty-enabled Provider

An umbrella term referring to any Provider offering any ID-FF-, ID-WSF-, or ID-SIS-based services.

Liberty-Enabled Client and Proxy Profile

This profile specifies interactions between Liberty-enabled clients and/or proxies, service providers, and identity providers [LibertyBindProf].

Liberty-enabled Proxy (LEP)

A Liberty-enabled proxy is a HTTP proxy (typically a WAP gateway) that emulates a Liberty-enabled client.

Liberty-enabled User Agent or Device (LUAD)

A user agent or device that has specific support for one or more profiles of the Liberty specifications. It should be noted that although a standard web browser can be used in many Liberty-specified scenarios, it does not provide specific support for the Liberty protocols, and thus is not a LUAD.

No particular claims of specific functionality should be implied about a system entity solely based on its definition as a LUAD. Rather, a LUAD may perform one or more Liberty system entity roles as defined by the Liberty specifications it implements. For example, a LUAD-LECP is a user agent or device that supports the Liberty LECP profile, and a LUAD-DS would define a user agent or device offering a Liberty ID-WSF Discovery Service.

local session state

In the Liberty context, this term refers to a notion of session state “local” to, i.e., maintained by, a provider, with respect to an interaction with another system entity, typically a user agent. Note that the concrete techniques used to maintain session state vary; cookies [RFC2965], so-called “URL re-writing”, and so-called “hidden form fields” are the most viable techniques in the HTTP, aka “web,” world.


The act of a Principal proving their identity to a system entity, which typically establishes a session.


The termination of a session.


See Liberty-enabled User Agent or Device.


Web Service Consumer (WSC), that may or may not also be a Liberty-enabled User Agent or Device.


A process or technique for achieving a result [Merriam-Webster].


see Message Exchange Pattern.

Message Exchange Pattern

A term, borrowed from [SOAPv1.2], for the overall notion of various patterns of message exchange between SOAP nodes. For example, request-reply and one-way are two MEPs used in this specification.

message thread

message thread is a synchronous exchange of messages in a request-response MEP between two SOAP nodes. All the messages of a given message thread are “linked” via each message’s <wsa:RelatesTo> header block value being set, by the sender, from the previous successfully received message’s <wsa:MessageID> header block value.


Definitional data that provides information about other data or system entities managed within an application or environment. In Liberty, metadata is Provider information that is necessary for interacting with Providers [LibertyMetadata].

network identity

An abstraction, consisting of a Principal‘s global set of attributes, which is composed from a “union” of the Principal’s accounts. See also identity.

Non-Transitive Proxy Capability

The ability to act for another entity based on Trusted Authority Policy. The capability is non-transferable.

opaque handle

An identifier that has meaning only in the context between a specific identity provider and specific service provider.

ordinary ID-* message

An ordinary ID-* message is a Liberty Identity Web Services Framework (ID-WSF) or Service Interface Specification (ID-SIS) message as defined in the [LibertyDST], [LibertyDisco], and [LibertyIDPP] specifications and others. It is “ordinary” as opposed to being a ID-* fault message message.

It has the characteristics of being designed to be conveyed by essentially any transport or transfer protocol, notably SOAP [SOAPv1.1]. It is also known among the ID-* specifications as a service request, or an ID-WSF (service) request, or an ID-SIS (service) request.


A Reversed HTTP binding for SOAP [SOAPv1.1] The primary difference from the normal HTTP binding for SOAP is that here a SOAP request is bound to a HTTP response and vice versa. “PAOS” is “SOAP” spelled backwards (pun intended).


See Policy Decision Point


See Policy Enforcement Point

People Service (PS)

An ID-WSF service that allows a Principal to share their social network information with different applications. The PS allows a Principal to manage, track, and group the relationships with their friends, family, and colleagues.


Privileges granted to a system entity with respect to operations that may be performed on some resource.

personally identifiable information (PII)

Any data that identifies or locates a particular person, consisting primarily of name, address, telephone number, e-mail address, bank accounts, or other unique identifiers such as Social Security numbers.


See personally identifiable information.


A logically defined, enforceable, and testable set of rules.

Policy Decision Point

A system entity that evaluates decision requests in light of applicable policy and information describing the requesting entity or entities and renders an authorization decision.

Policy Enforcement Point

A system entity that performs access control by making decision requests and enforcing authorization decisions. If the authorization decision is pushed to the PEP there will be no need for it to create a request.


Succinctly, a principal is a system entity whose identity can be authenticated. In Liberty usage, the term Principal is often synonymous with “natural person” or “user”. A Principal’s identity may be federated. Examples of Principals include individual users, groups of individuals, organizational entities, e.g. corporations, or a component of the Liberty architecture.

Principal identity

An identity being wielded by a Principal, or that is mapped to a Principal in some fashion.


Proper handling of personal information throughout its life cycle, consistent with the preferences of the subject.

processing context

processing context is the collection of specific circumstances under which a particular processing step or set of steps take place.

processing context facet

processing context facet is an identified aspect, inherent or additive, of a processing context.


Profile is used in two distinct senses in Liberty specifications:

  1. Data comprising the broad set of attributes that may be maintained on behalf of a system entity (typically a Principal), over and beyond the entity’s various identifiers. At least some of this information (for example, addresses, preferences, and card numbers) is typically provided by the Principal.
  2. A profile of some specification. For example, the Discovery Service specification [LibertyDisco] profilesWeb Services Addressing specifications [WSAv1.0] [WSAv1.0-SOAP], and the Security Mechanisms specifications [LibertySecMech] profile SAML [SAMLCore2].

protocol endpoint

A communication point from which data may be sent or received.

See also endpointID-WSF Endpoint Reference.


provider is a Liberty-enabled entity that performs one or more of the provider roles in the Liberty architecture, for example Service Provider or Identity Provider. Providers are identified in Liberty protocol interactions by their Provider IDs or optionally their Affiliation ID if they are a member of an affiliation(s) and are acting in that capacity.

Provider ID

Provider ID identifies an entity known as a provider. It is schematically represented by the providerID attribute of the <EntityDescriptor> metadata element [LibertyMetadata].


  1. (1) An entity authorized to act for another [Merriam-Webster].
  2. (2) A system entity whose authenticated identity, according to the recipient, differs from that of the system entity making the invocation under consideration.


An arbitrary identifier assigned by the identity or service provider to identify a Principal to a given relying party so that the name has meaning only in the context of the relationship between the parties.


An entity that receives a message and acts as the message’s ultimate processor.


See Rights Expression Languages.


role taken by a system entity when it receives a message sent by another system entity. See also SOAP receiver in [SOAPv1.2].

relying party

The recipient of a message that relies on a request message and associated assertions to determine whether to provide a requested service.


system entity which sends a service request to a provider.


Resource is one of those terribly overloaded terms in the computer science and distributed systems realms. As used in various Liberty specifications, it has (at least) two definitions, depending on whether one is using the term in an identity-based context (1) or not (2):

  1. Resource refers to either data related to some identity or identities, or a service acting on behalf of some identity or group of identities. An example of an identity-based resource is a Principal’s calendar service.
  2. A resource is whatever might be identified with a URI, although often there is a connotation that one might be able to obtain information of some sort from said “resource.”

resource offering

The association of a resource and a service instance.

This term is superseded in ID-WSFv2 by ID-WSF Endpoint Reference (ID-WSF EPR)

Rights Expression Language (REL)

Rights Expression Language facilitates the expression of who are the “rights holders” for a resource, who is authorized to use a resource and their applicable permissions, and any constraints or conditions imposed on such permissions. They also may express “rights entities” and “rights transactions”.


A function or part performed, especially in a particular operation or process [Merriam-Webster].

SAML (Security Assertion Markup Language)

An XML-based standard defining a means for making assertions about events, attributes, and policy evaluations concerning subjects [SAMLCore11]. In Liberty usage, SAML subjects are typically Principals.

SAML assertion

See assertion.

SAML Authority

An abstract system entity in the SAML domain model that issues assertions [SAMLGloss2].


See Simple Authentication and Security Layer.

SASL mechanism

SASL mechanism is an authentication mechanism that has been profiled for use in the context of SASL [RFC4422]. See [RFC2444] for a particular example of profiling an existing authentication mechanism ó one-time passwords [RFC2289] ó for use as a SASL mechanism. See also [LibertyAuthn].

security token

In Liberty, a security token is a collection of security-related information that is used to represent and substantiate a claim [LibertyIDWSFSecurityPrivacyGuidelines] [LibertySecMech].

Outside of Liberty, the term “security token” often refers to hardware-based devices, e.g., so-called “token cards.” One should not confuse the latter and the former definitions. However, it is possible for some given authentication mechanism to employ token cards in the process of authentication.


  1. (1) A role donned by a system entity when it constructs and sends a message to another system entity. See also SOAP sender in [SOAPv1.2].
    1. (1a) an initial SOAP sender. A sender is a proxy when its identity differs from the invocation identity.


role donned by a system entity that provides a service in response to requests from other system entities called clients [RFC2828]. Note that in order to provide a service to clients; a server will often be both a sender and a receiver.


  1. (1) A collection of endpoints designed to offer some service or to provide information [WSDLv1.1].
  2. (2) Short form of ID-WSF Service or ID-WSF-based Service.

service discovery

The act of looking up a service(s) in the Discovery Service.

service instance

The physical instantiation of a service. A service instance is a web service at a distinct endpoint.

See also ID-WSF Endpoint Reference.

service instance address

An address of a service instance, typically expressed in URI syntax [RFC3622].

Service Provider (SP)

  1. (1) A role donned by system entities. In the Liberty architecture, Service Providers interact with other system entities primarily via vanilla HTTP.
  2. (2) From a Principal’s perspective, a Service Provider is typically a website providing services and/or goods.

service request

service request is another term for an ordinary ID-* message sent by a client. Service request is also loosely equivalent to a “SOAP-bound (ordinary) ID-* message”.

Service Type URI

ID-WSF-based services are assigned a Service Type URI as a part of each service’s definition. The Service Type URI is a factor in service discovery [LibertyDisco].


[Merriam-Webster] defines session (in its sixth sense [sic]) as: “a meeting or period devoted to a particular activity” [as in “an Irish drinking session” Ed.]. Thus, a given interaction between some set of system entities may involve a notion of session, especially if one or more of the system entities maintain session state.

session state

If an interaction between system entities involves one or more of the system entities maintaining information pertaining to the interaction itself ó such as who the other involved system entity(ies) are, when the interaction began, etc. ó then there likely is an explicit notion of session and thus this information is termed session state information.

See also local session state.

SASL [RFC4422] is an approach to modularizing protocol design such that the security design components, e.g., authentication and security layer mechanisms, are reduced to a uniform abstract interface. This facilitates a protocol’s use of an open-ended set of security mechanisms, as well as a so-called “late binding” between implementations of the protocol and the security mechanisms’ implementations. This late binding can occur at implementation- and/or deployment-time. The SASL specification also defines how one packages authentication and security layer mechanisms to fit into the SASL framework, where they are known as SASL mechanisms, as well as register them with the Internet Assigned Numbers Authority [IANA] for reuse.

single sign-on (SSO)

From a Principal‘s perspective, single sign-on encompasses the capability to authenticate with some system entity ó in the Liberty context, an Identity Provider ó and have that authentication honored by other system entities, termed Service Providers in the Liberty context.

Note that upon authenticating with an Identity Provider, the Identity Provider typically establishes and maintains some notion of local session state between itself and the Principal’s user agent. Service Providers may also maintain their own distinct local session state with a Principal’s user agent.

Single Sign-On Service (SSO Service, SSOS)

An ID-WSF-based service providing WSCs a means of obtaining ID-FF authentication assertions [LibertyAuthn].

Single Sign-On Service Consumer (SSO Service Consumer, SSOS Consumer)

Web Service Consumer (WSC) implementing the client-side of the ID-WSF Single Sign-On Service [LibertyAuthn].

Single Sign-On Service Provider (SSO Service Provider, SSOS Provider)

Web Service Provider (WSP) implementing the server-side of the ID-WSF Single Sign-On Service [LibertyAuthn].

SOAP (Simple Object Access Protocol)

An XML envelope and data encoding technology used to communicate information and requests across the Web. It is typically considered the protocol used by Web services. It is actually an envelope encapsulation format that can be used with lower level Web protocols such as HTTP and FTP. See [SOAPv1.1] and [SOAPv1.2].

SOAP-bound ID-* message

SOAP message conveying ID-WSF and perhaps ID-SIS header blocks and conveying either an ordinary ID-* message or an ID-* fault message. After being bound to SOAP, the resultant composite messages are referred to as an Ordinary SOAP-bound ID-* Message and a SOAP-bound ID-* Fault Message, respectively.

SOAP header block

A [SOAPv1.2] term meaning: An [element] used to delimit data that logically constitutes a single computational unit within the SOAP header. In [SOAPv1.1] these are known as simply SOAP headers, or simply headers. Liberty specifications borrow the SOAPv1.2 terminology.

SOAP node

A [SOAPv1.2] term describing system entities who are parties to SOAP-based message exchanges that are, for purposes of this specification, also the ultimate destination of the exchanged messages, i.e., SOAP endpoints. In [SOAPv1.1], SOAP nodes are referred to as SOAP endpoints, or simply endpoints. The Liberty specifications borrow the SOAPv1.2 terminology.


See Service Provider.

SSL (Secure Sockets Layer Protocol)

An Internet protocol (originally developed by Netscape Communications, Inc.) that uses connection-oriented end-to-end encryption to provide data confidentiality service and data integrity service for traffic between a client (often a Web browser) and a server and that can optionally provide peer entity authentication between the client and the server. See Transport Layer Security. [RFC2828].


See single sign-on.

SSOS, SSO Service

See Single Sign-On Service.

SSOS Provider, SSO Service Provider

See Single Sign-On Service Provider.

system entity

An active element of a computer/network system. For example, an automated process or set of processes, a subsystem, a person or group of persons that incorporates a distinct set of functionality [SAMLGloss2].

TLS (Transport Layer Security Protocol)

An evolution of the SSL protocol. The TLS protocol provides communications privacy over the Internet. The protocol allows client/server applications to communicate in a way that is designed to prevent eavesdropping, tampering, or message forgery. See [RFC4346].


See security token.

trust circle

See Circle of Trust.

Trusted Authority

In Liberty, a Trusted Third Party (TTP) which issues and vouches for assertions, otherwise known as an Identity Provider.

Trusted Third Party

In general, a security authority or its agent, trusted by other entities with respect to security-related activities. In the context of Liberty, these other entities are, for example,

Principals and Service Providers, and the trusted third party is typically the Identity Provider(s) involved in the particular interaction of interest.


See Trusted Third Party

URI (Uniform Resource Identifier)

A compact string of characters for identifying an abstract or physical resource. [RFC3986] defines the generic syntax of URIs. URNs and URLs are proper subsets of URIs.

URL (Uniform Resource Locator)

URLs identify resources via a representation of their primary access mechanism (e.g., their network location) rather than identifying the resource by name or by some other attributes of that resource [RFC3986]. URLs are a proper subset of URIs.

URN (Uniform Resource Name)

Persistent, location-independent, resource names with delegatable sub-namespaces, termed Uniform Resource Name (URN) Namespaces [RFC2141]. Liberty’s URN Namespace is defined in [RFC3622]. URNs are a proper subset of URIs.

user agent

Software that a “natural person” interacts with directly. A user agent typically implements a user interface. A typical user agent is a web browser. A more specialized sort of user agent is the Liberty-enabled User Agent or Device (LUAD).

user interface

The controls (such as menus, buttons, prompts, etc.) and mechanisms (such as selection and focus) provided by, e.g., a user agent.

web service

  1. (1) Generically, a service defined in terms of an XML-based protocol, typically transported over SOAP, and/or a service whose instances, and possibly data objects managed therein, are concisely addressable via URIs. Such a generic web service (gWS) may be defined in various standardized and/or proprietary contexts.Various organizations, formal or ad-hoc, have their own particular definitions for this term. For example, the W3C’s definition (see ) is:There are many things that might be called “Web services” in the world at large. However, for the purpose of this Working Group and this architecture, and without prejudice toward other definitions, we will use the following definition:A Web service is a software system designed to support interoperable machine-to-machine interaction over a network. It has an interface described in a machine-processable format (specifically WSDL). Other systems interact with the Web service in a manner prescribed by its description using SOAP-messages, typically conveyed using HTTP with an XML serialization in conjunction with other Web-related standards.
  2. (2) As specifically used in Liberty specifications, usually in terms of WSCs and WSPs, it means a web service that’s defined in terms of the ID-* “stack”, and thus utilizes [LibertySOAPBinding], [LibertySecMech], and is “discoverable” [LibertyDisco]. See also identity web service.

Note that Liberty Identity Web Services also meets the W3C definition.

Web Service Consumer

role donned by a system entity when it makes a request to a web service.

Web Services Description Language

A means to describe the interface of a Web service. See [WSDLv1.1].

Web Service Provider

role donned by a system entity when it provides a web service.

WML (Wireless Markup Language)

A markup language based on XML and intended for use in specifying content and user interface for narrowband devices, including cellular phones and pagers.


See Web Service Consumer.


See Web Services Description Language.


See Web Service Provider.

X.509 token

An X.509 token is a type of security token containing an X.509 public key certificate.

XML (eXtensible Markup Language)

A W3C technology for encoding information and documents for exchange over the Web. See [XML], [XMLCanon], [XMLDsig], [xmlenc-core], [Schema1-2], and [Schema2-2]



[LibertyAuth] – Hodges, Jeff, Aarts, Robert, Madsen, Paul, Cantor, Scott, eds. ” Liberty ID-WSF Authentication, Single Sign-On, and Identity Mapping Services Specification ,” Version v2.0, Liberty Alliance Project (30 July, 2006). liberty-idwsf-authn-svc-v2.0.pdf

[LibertyAuthnContext] – Madsen, Paul, eds. “Liberty ID-FF Authentication Context Specification,” Version 2.0-01, Liberty Alliance Project (21 November 2004). draft-liberty-authentication-context-v2.0-01.pdf

[LibertyBindProf] – Cantor, Scott, Kemp, John, Champagne, Darryl, eds. “Liberty ID-FF Bindings and Profiles Specification,” Version 1.2-errata-v2.0, Liberty Alliance Project (12 September 2004). draft-liberty-idff-bindings-profiles-1.2-errata-v2.0.pdf

[LibertyDisco] – Hodges, Jeff, Cahill, Conor, eds. “Liberty ID-WSF Discovery Service Specification,” Version 2.0, Liberty Alliance Project (30 July, 2006). liberty-idwsf-disco-svc-v2.0.pdf

[LibertyDST] – Kellomäki, Sampo, Kainulainen, Jukka, eds. “Liberty ID-WSF Data Services Template,” Version 2.1, Liberty Alliance Project (30 July, 2006). liberty-idwsf-dst-v2.1.pdf

[LibertyIDEP] – Kellomäki, Sampo, Lockhart, Rob, eds. “Liberty ID-SIS Employee Profile Service Specification,” Version 1.1, Liberty Alliance Project (29 September, 2005). liberty-idsis-ep-v1.1.pdf

[LibertyIDPP] – Kellomäki, Sampo, Lockhart, Rob, eds. “Liberty ID-SIS Personal Profile Service Specification,” Version 1.1, Liberty Alliance Project (29 September, 2005). liberty-idsis-pp-v1.1.pdf

[LibertyInteract] – Aarts, Robert, Madsen, Paul, eds. “Liberty ID-WSF Interaction Service Specification,” Version 2.0, Liberty Alliance Project (30 July, 2006). liberty-idwsf-interaction-svc-v2.0.pdf

[LibertyIDWSFSecurityPrivacyGuidelines] – Landau, Susan, eds. “Liberty ID-WSF Security and Privacy Overview,” Version 1.0, Liberty Alliance Project (8 October 2003). liberty-idwsf-security-privacy-overview-v1.0.pdf

[LibertyMetadata] – Davis, Peter, eds. “Liberty Metadata Description and Discovery Specification,” Version 2.0-02, Liberty Alliance Project (25 November 2004). draft-liberty-metadata-v2.0-02.pdf

[LibertyPeopleService] – Koga, Yuzo, Madsen, Paul, eds. “Liberty ID-WSF People Service Specification,” Version 1.0, Liberty Alliance Project (30 July, 2006). liberty-idwsf-people-service-v1.0.pdf

[LibertySecMech] – Hirsch, Frederick, eds. “Liberty ID-WSF Security Mechanisms Core,” Version v2.0, Liberty Alliance Project (30 July, 2006). liberty-idwsf-security-mechanisms-core-v2.0.pdf

[LibertySecMech20SAML] – Hirsch, Frederick, eds. “Liberty ID-WSF Security Mechanisms Core,” Version v2.0, Liberty Alliance Project (30 July, 2006). liberty-idwsf-security-mechanisms-saml-profile-v2.0.pdf

[LibertySOAPBinding] – Hodges, Jeff, Kemp, John, Aarts, Robert, Whitehead, Greg, Madsen, Paul, eds. “Liberty ID-WSF SOAP Binding Specification,” Version 2.0, Liberty Alliance Project (30 July, 2006). liberty-idwsf-soap-binding-v2.0.pdf

[LibertyProtSchema] – Cantor, Scott, Kemp, John, eds. “Liberty ID-FF Protocols and Schema Specification,” Version 1.2-errata-v3.0, Liberty Alliance Project (14 December 2004). draft-liberty-idff-protocols-schema-1.2-errata-v3.0.pdf

[RFC2119] – S. Bradner “Key words for use in RFCs to Indicate Requirement Levels,” RFC 2119, The Internet Engineering Task Force (March 1997).

[RFC2141] – Moats, R., eds. (May 1997). “URN Syntax,” RFC 2141, Internet Engineering Task Force.

[RFC2616] – Fielding, R., Gettys, J., Mogul, J., Frystyk, H., Masinter, L., Leach, P., Berners-Lee, T., eds. (June 1999). “Hypertext Transfer Protocol – HTTP/1.1,” RFC 2616, The Internet Engineering Task Force.

[RFC2828] – Shirey, R., eds. (May 2000). “Internet Security Glossary,” RFC 2828., Internet Engineering Task Force.

[RFC3280] – Housley, R., eds. (April 2002). “Internet X.509 Public Key Infrastructure Certificate and Certificate Revocation List (CRL) Profile,” RFC 3280, The Internet Engineering Task Force.

[RFC3622] – Mealling, M., eds. (February 2004). “A Uniform Resource Name (URN) Namespace for the Liberty Alliance Project,” RFC 3622, The Internet Engineering Task Force.

[RFC3986] – Berners-Lee, T., Fielding, R., Masinter, L., eds. (January 2005). “Uniform Resource Identifier (URI): Generic Syntax,” RFC 3986 (Obsoletes RFC2732, RFC2396, RFC1808) (Updates RFC1738) (Also STD0066) (Status: STANDARD), The Internet Engineering Task Force.

[RFC4120] – Neuman, C., Yu, T., Hartman, S., Raeburn, K., eds. (July 2005). “The Kerberos Network Authentication Service (V5),” RFC 4120, The Internet Engineering Task Force.

[RFC4346] – Dierks, T., Rescorla, E., eds. (April 2006). “The Transport Layer Security (TLS) Protocol,” Version 1.1 RFC 4346, Internet Engineering Task Force.

[RFC4422] – “Simple Authentication and Security Layer (SASL),” Melnikov, A., Zeilenga, K., eds. (June 2006). RFC 4422, Internet Engineering Task Force.

[SAMLBind11] – Maler, Eve, Mishra, Prateek, Philpott, Rob, eds. (2 September 2003). “Bindings and Profiles for the OASIS Security Assertion Markup Language (SAML) V1.1,” SAML V1.1, OASIS Standard, Organization for the Advancement of Structured Information Standards.

[SAMLCore11] – Maler, Eve, Mishra, Prateek, Philpott, Rob, eds. (2 September 2003). “Assertions and Protocol for the OASIS Security Assertion Markup Language (SAML) V1.1,” SAML v1.1, OASIS Standard, Organization for the Advancement of Structured Information Standards.

[SAMLCore2] – Cantor, Scott, Kemp, John, Philpott, Rob, Maler, Eve, eds. (15 March 2005). “Assertions and Protocol for the OASIS Security Assertion Markup Language (SAML) V2.0,” SAML V2.0, OASIS Standard, Organization for the Advancement of Structured Information Standards.

[SAMLGloss2] – Hodges, Jeff, Philpott, Rob, Maler, Eve, eds. (15 March 2005). “Glossary for the OASIS Security Assertion Markup Language (SAML) V2.0,” SAML 2.0, OASIS Standard, Organization for the Advancement of Structured Information Standards.

[Schema1-2] – Thompson, Henry S., Beech, David, Maloney, Murray, Mendelsohn, Noah, eds. (28 October 2004). “XML Schema Part 1: Structures Second Edition,” Recommendation, World Wide Web Consortium.

[Schema2-2] – Biron, Paul V., Malhotra, Ashok, eds. (28 October 2004). “XML Schema Part 2: Datatypes Second Edition,” Recommendation, World Wide Web Consortium.

[SOAPv1.1] – “Simple Object Access Protocol (SOAP) 1.1,” Box, Don, Ehnebuske, David , Kakivaya, Gopal, Layman, Andrew, Mendelsohn, Noah, Nielsen, Henrik Frystyk, Winer, Dave, eds. World Wide Web Consortium W3C Note (08 May 2000).

[SOAPv1.2] – “SOAP Version 1.2 Part 1: Messaging Framework,” Gudgin, Martin, Hadley, Marc, Mendelsohn, Noah, Moreau, Jean-Jacques, Nielsen, Henrik Frystyk, eds. World Wide Web Consortium W3C Recommendation (07 May 2003).

[WSDLv1.1] – “Web Services Description Language (WSDL) 1.1,” Christensen, Erik, Curbera, Francisco, Meredith, Greg, Weerawarana, Sanjiva, eds. World Wide Web Consortium W3C Note (15 March 2001).

[wss-saml11] – “Web Services Security: SAML Token Profile 1.1,” OASIS Public Review Draft 01. Monzillo, Ronald, Kaler, Chris, Nadalin, Anthony, Hallam-Baker, Phillip, eds. (June 28, 2005). Organization for the Advancement of Structured Information Standards.

[TrustInCyberspace] – Schneider, Fred B., eds. “Trust in Cyberspace,” National Research Council (1999).

[XML] – Bray, Tim, Paoli, Jean, Sperberg-McQueen, C. M., Maler, Eve, Yergeau, Francois, eds. (04 February 2004). “Extensible Markup Language (XML) 1.0 (Third Edition),” Recommendation, WorldWideWeb Consortium.

[XMLDsig] – Eastlake, Donald, Reagle, Joseph, Solo, David, eds. (12 Feb 2002). “XML-Signature Syntax and Processing,” Recommendation, World Wide Web Consortium.

[XMLCanon] – Boyer, John, Eastlake, Donald, Reagle, Joseph, eds. (18 July 2002). “Exclusive XML Canonicalization,” Recommendation, World Wide Web Consortium.

[xmlenc-core] – Eastlake, Donald, Reagle, Joseph, eds. (10 December 2002). “XML Encryption Syntax and Processing,” W3C Recommendation, World Wide Web Consortium.


[IANA] – “The Internet Assigned Numbers Authority,”

[Merriam-Webster] – “Merriam-Webster Dictionary,”

[RFC2289] – “A One-Time Password System,” N. Haller C. Metz P. Nessner M. Straw (February 1998). RFC 2289, Internet Engineering Task Force.

[RFC2444] – Newman, C., eds. (October 1998). “The One-Time-Password SASL Mechanism,” RFC 2444, The Internet Engineering Task Force.

[RFC2965] – Kristol, D., Montulli, L., eds. (October 2000). “HTTP State Management Mechanism,” RFC 2965., Internet Engineering Task Force.

[WSAv1.0] – “Web Services Addressing (WS-Addressing) 1.0,” Gudgin, Martin, Hadley, Marc, Rogers, Tony, eds. World Wide Web Consortium W3C Recommendation (9 May 2006).


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