*Editor’s note: To read Part I of this article, click here. To read Part II of this article, click here
The identity management standards jungle
A critical aspect of the new identity management architecture blueprint I discussed in my previous article is that it needs to be based on a clear separation of identity management concerns. This means that identity and access services – authentication, access control, logging and audit, federation – need to be delivered as shared infrastructure services, governed by a unified policy management layer and underpinned by a federated identity data repository. It also means that these shared identity services should make use of other infrastructure services, such as workflow management, and must be usable by the broader application and IT infrastructure. At the same time the identity and access services, particularly authentication and access control, must be autonomous – to allow entitlements, for example, to be varied in accordance with available authentication facilities.
The upshot of all of this is that the boundaries between the layers of identity management infrastructure are critical to get right. The importance of this is elevated because it is highly unlikely that most organisations will have the luxury of a rip-and-replace strategy or the ability to satisfy all of their identity management requirements with the offerings of a single vendor. Each layer should present a common interface to all services that depend on the functionality of that layer, and open standard protocols and data formats are non-negotiable for those common interfaces to facilitate interoperability.
So where will these standards, which are so important, come from? Today there is a fast-moving and confusing range of standards at differing levels of maturity, focussed on particular identity management capabilities, including:
Service Provisioning Markup Language (SPML) – focussed on providing standard, technology independent mechanisms for provisioning request and response message exchange. SPML standardises the format of requests to maintain and search provisioning data, as well as to discover information about that provisioning data. However, SPML is yet to receive broad vendor support
Security Assertion Markup Language (SAML) – focussed on providing standard, technology-independent mechanisms for exchanging security credentials between parties. SAML is based on the notion of assertions, which consist of one or more statements issued by SAML authorities. SAML can be used in web single sign-on scenarios based on HTTP SAML assertion exchange – also called passive – and in application-to-application scenarios based on web services – also called active. SAML is supported by all of the leading identity management vendors
eXtensible Access Control Markup Language (XACML) – focussed on providing standard, technology independent mechanisms for the definition of authorisation and access control policies, in the form of rules, and their subsequent distribution to the solutions responsible for enforcing them. XACML is yet to receive broad vendor support
A set of WS-* specifications – a series of web services-based standards focussed on security token format exchange (WS-Trust); the establishment of shared security contexts to enable multiple secure request/response message exchanges (WS-SecureConversation); the definition and exchange, based on WS-Policy, of security policies for use with WS-Security, WS-Trust and WS-SecureConversation (WS-SecurityPolicy); and the federation of identity, attribute, authentication and authorisation information through the coordination of WS-Trust interactions (WS-Federation). The WS-* identity management specifications are supported by many of the leading identity management vendors, particularly IBM and Microsoft
Liberty Alliance standards – the Liberty Alliance is developing a variety of standards-based initiatives focussed around federated identity management. These initiatives are based on SAML and include ID-FF, which is focussed on human-to-application interaction; and ID-WSF, which is focussed on application-to-application interaction. ID-WSF forms the basis for ID-SIS (Service Interface Specifications), a set of consumer-oriented identity services. These services address requirements such as geo-location, contact data sharing, presence and the sharing of social applications and information, such as bookmarking, blogging and digital photos, by allowing others within their social networks to access those services without their own login. The Liberty Alliance specifications are supported by the majority of the leading identity management vendors, with the notable exception of Microsoft which provides some interoperability through work undertaken with Sun Microsystems
User-centric identity initiatives – a variety of initiatives are underway focussed on user-centric identity, many of them URL or URI-based, including XRI, XDI, i-names/i-numbers, Light-Weight Identity (LID), OpenID and Yadis (Yet Another Decentralized Interoperability System, focussed on interoperability of URL-based identity systems). Although these are being adopted in the world of online services they have so far received only limited support from vendors focussed on the enterprise identity management market.
If this wasn’t enough, a number of open source development projects are underway which complement these various standards initiatives. The Higgins Project, under the auspices of the Eclipse Foundation, is developing a software framework to insulate developers from the complexity of multiple identity management systems and standards. The Novell-sponsored Bandit Project, meanwhile, is building on Higgins to provide open, standards-based implementations of common identity management capabilities, such as role evaluation and event generation for auditing. Finally, there is the recently formed Apache Software Foundation’s Heraldry Identity Project, which is setting out to bring lightweight URL/XRI-based identities to the desktop by combining the Yadis identity service discovery protocol with the OpenID single sign-on authentication protocol into a common desktop component, exploiting a possible open source implementation of Microsoft’s CardSpace (formerly InfoCard).
It is still comparatively early days in the world of identity management standards and even where they are comparatively mature there are competing alternatives. In common with much of the work on web services standards, standardisation work so far has focussed on protocol-level interoperability at the expense of semantics (such as how to map roles between organisations). A number of specifications, such as SPML and XACML, have yet to receive widespread adoption. Federated identity management remains an area of confusion, with the work of the Liberty Alliance and the WS-* specification both vying for dominance.
My final article in this series will discuss what you should do in the face of this standards confusion and outline some other steps you should take to establish an identity management architecture and approach to provide a foundation to respond to the broad range of business requirements discussed in the first article.
About the Author
Neil Macehiter is a co-founder of and Research Director at Macehiter Ward-Dutton, a specialist IT advisory firm which focuses exclusively on issues concerning IT-business alignment – including IT architecture, integration, management, organisation and culture.
Neil specialises in enterprise architecture/SOA, web services, virtualisation and identity management. Immediately prior to forming Macehiter Ward-Dutton, he was Ovum’s Research Director for enterprise architecture topics, leading a team of analysts covering software development, deployment and management issues.
Before that he spent fourteen years in a range of consulting and sales support roles for a number of the largest IT suppliers, including Oracle and Sun Microsystems, and latterly in product and corporate strategy for a number of European start-ups, including Autonomy and Zeus Technology.
Neil has acted as an advisor to leading vendors, including IBM, Oracle, Microsoft and Sun Microsystems; and to large IT user organisations, including the Australian Government’s Centrelink department, the Netherlands’ Government’s Belastingdienst agency, The UK Government’s Department of Work and Pensions and The Government of Hong Kong.
Neil is a regular speaker at conferences throughout Europe and is regularly quoted in mainstream and IT specialist media, including the BBC, Computer Weekly, The FT, The Times and IT Week. Neil earned an MA in Natural Sciences from Cambridge University in 1985.
Macehiter Ward-Dutton is a specialist IT advisory firm which combines industry research and analysis with tailored consulting services, and is focused exclusively on issues surrounding IT-business alignment.
The company was formed in February 2005 by two top-level analysts formerly of Ovum: Neil Ward-Dutton and Neil Macehiter.