1 Web Standards and the HyLiFe Project (including authentication and distributed searching) Brian Kelly Address UK Web Focus UKOLNURL University of Bath UKOLN is funded by the British Library Research and Innovation Centre, the Joint Information Systems Committee of the Higher Education Funding Councils, as well as by project funding from the JISC’s Electronic Libraries Programme and the European Union. UKOLN also receives support from the University of Bath where it is based.

2 UK Web Focus / W3C UK Web Focus: JISC funded post based at UKOLN (Bath Univ) Advises UK HE community on web issues Represents JISC on W3C W3C ( World Wide Web Consortium ): International consortium, with headquarters at MIT, INRIA and Keio University (Japan) Coordinates development of web protocols Four domains: Architecture Technology & Society User Interface Web Accessibility

3 What Are Your Interests? What interests do you have in web standards and technologies?

4 Contents Introduction Web Standards Overview Web Standards: Data Formats Transport Addressing Metadata Distributed Searching Authentication Deployment Issues Questions Aims of Talk To give brief overview of web architecture To describe developments to web standards To review emerging developments with metadata, distributed searching and authentication To briefly address implementation models Aims of Talk To give brief overview of web architecture To describe developments to web standards To review emerging developments with metadata, distributed searching and authentication To briefly address implementation models

5 Standardisation W3C Produces W3C Recommendations on Web protocols Managed approach to developments Protocols initially developed by W3C members Decisions made by W3C, influenced by member and public review IETF Produces Internet Drafts on Internet protocols Bottom-up approach to developments Protocols developed by interested individuals "Rough consensus and working code" ISO Produces ISO Standards Can be slow moving and bureaucratic Produce robust standards Proprietary De facto standards Often initially appealing (cf PowerPoint, PDF) May emerge as standards PNG HTML Z39.50 Java? PNG HTML Z39.50 Java? PNG HTML HTTP PNG HTML HTTP URN whois++ HTTP URN whois++ HTML extensions PDF and Java? HTML extensions PDF and Java?

6 The Web Vision Tim Berners-Lee's (and W3C's) vision for the Web: Evolvability is critical Automation of information management: If a decision can be made by machine, it should All structured data formats should be based on XML Migrate HTML to XML All logical assertions to map onto RDF model All metadata to use RDF See keynote talk at WWW 7 conference at

7 Web Protocols Web initially based on three simple protocols: Data Formats HTML (HyperText Markup Language) provides the data format for native documents Addressing URLs (Uniform Resource Locator) provides an addressing mechanism for web resources Transport HTTP (HyperText Transfer Protocol) defines transfer of resources between client and server Data Format HTML Addressing URL Transport HTTP

8 HTML History HTML 1.0Unpublished specification. HTML 2.0Spec. based on innovations from NCSA (forms and inline images!) HTML 3.0Proposed spec. (renamed from HTML+). Very comprehensive Failed to complete IETF standardisation Little implementation experience ProprietaryIntroduction of proprietary HTML elements by Netscape and Microsoft HTML 3.2Spec. based on description of mainstream innovations in marketplace HTML 4.0Current recommendation Dilemma Proprietary extensions cause problems. But experiments are needed

9 HTML 4.0, CSS 2.0 and DOM HTML 4.0 used in conjunction with CSS 2.0 (Cascading Style Sheets) and the DOM provides an architecturally pure, yet functionally rich environment HTML W3C-Rec Improved forms Hooks for stylesheets Hooks for scripting languages Table enhancements Better printing CSS W3C-Rec Support for all HTML formatting Positioning of HTML elements Multiple media support CSS Problems Changes during CSS development Netscape & IE incompatibilities Continued use of browsers with known bugs CSS Problems Changes during CSS development Netscape & IE incompatibilities Continued use of browsers with known bugs DOM - W3C-Rec Document Object Model Hooks for scripting languages Permits changes to HTML & CSS properties and content

10 HTML Limitations HTML 4.0 / CSS 2.0 have limitations: Difficulties in introducing new elements –Time-consuming standardisation process ( ) –Dictated by browser vendor (, ) Area may be inappropriate for standarisation: –Covers specialist area (maths, music,...) –Application-specific ( ) HTML is a display (output) format HTML's lack of arbitrary structure limits functionality: –Find all memos copied to John Smith –How many unique tracks on Jackson Browne CDs

11 XML XML: Extensible Markup Language A lightweight SGML designed for network use Addresses HTML's lack of evolvability Arbitrary elements can be defined (,, etc) Agreement achieved quickly - XML 1.0 became W3C Recommendation in Feb 1998 Support from industry (SGML vendors, Microsoft, etc.) Support in Netscape 5 and IE 5

12 XML Concepts Well-formed XML resources: Make end-tags explicit:... Make empty elements explicit: Quote attributes <IMG SRC="logo" HEIGHT="20" Use consistent upper/lower case Valid XML resources: Need DTD XML Namespaces: Mechanism for ensuring unique XML elements : Insert M-471

13 XML Deployment Ariadne issue 15 has article on "What Is XML?" Describes how XML support can be provided: Natively by new browsers Back end conversion of XML - HTML Client-side conversion of XML - HTML / CSS Java rendering of XML Examples of intermediaries See

14 XLink, XPointer and XSL XLink will provide sophisticated hyperlinking missing in HTML: Links that lead user to multiple destinations Bidirectional links Links with special behaviors: –Expand-in-place / Replace / Create new window –Link on load / Link on user action Link databases XPointer will provide access to arbitrary portions of XML resource XSL stylesheet language will provide extensibility and transformation facilities (e.g. create a table of contents) England France

15 XML Update Data / Schemas XML-Data: Submitted to W3C Jan 98 (Obsolete?) Document Content Description: Submitted Aug 98 XSchema: Independent effort Programming Interface DOM level 1: W3C Recommendation, May 98 Style & Presentation CSS level 2: W3C Recommendation, May 98 Extensible Style Language: Working Draft, Aug 98 Relationship to Other Resources XLink, XPointer: Working Drafts, Mar 98 XML Namespaces: Working Draft, Aug 98 Query Languages XML Query Language: Submitted to W3C Aug 98 XQL: Independent effort

16 Addressing URLs (e.g. ) have limitations: Lack of long-term persistency –Organisation changes name –Department shut down or merged –Directory structure reorganised Inability to support multiple versions of resources (mirroring) URNs (Uniform Resource Names): Proposed as solution Difficult to implement (no W3C activity in this area)

17 Addressing - Solutions DOIs (Document Object Identifiers): Proposed by publishing industry as a solution Aimed at supporting rights ownership Business model needed PURLs (Persistent URLs): Provide single level of redirection Pragmatic Solution: URLs don't break - people break them Design URLs to have long life-span Further information:

18 Transport HTTP/0.9 and HTTP/1.0:  Design flaws and implementation problems HTTP/1.1: Addresses some of these problems 60% server support Performance benefits! (60% packet traffic reduction)  Is acting as fire-fighter  Not sufficiently flexible or extensible HTTP/NG: Radical redesign using object-oriented technologies Undergoing trials Gradual transition (using proxies) Integration of application (distributed searching?)

19 Metadata Metadata - the missing architectural component from the initial implementation of the web Metadata - RDF PICS, TCN, MCF, DSig, DC,... Addressing URL Data format HTML Transport HTTP Metadata Needs: Resource discovery Content filtering Authentication Improved navigation Multiple format support Rights management Metadata Needs: Resource discovery Content filtering Authentication Improved navigation Multiple format support Rights management

20 Metadata Examples DSig (Digital Signatures initiative): Key component for providing trust on the web DSig 2.0 will be based on RDF and will support signed assertion: –This page is from the University of Bath –This page is a legally-binding list of courses provided by the University P3P (Platform for Privacy Preferences): Developing methods for exchanging Privacy Practices of Web sites and user Note that discussions about additional rights management metadata are currently taking place

21 RDF RDF (Resource Description Framework): Highlight of WWW 7 conference Provides a metadata framework ("machine understandable metadata for the web") Based on ideas from content rating (PICS), resource discovery (Dublin Core) and site mapping (MCF) Applications include: –cataloging resources– resource discovery –electronic commerce– intelligent agents –digital signatures– content rating –intellectual property rights– privacy See

22 RDF Model RDF: Based on a formal data model (direct label graphs) Syntax for interchange of data Schema model Resource Value PropertyType Property page.html £0.05 Cost 11-May-98 ValidUntil RDF Data Model page.html £ May-98 Property Cost InstanceOf ValidUntil Value PropObj Cost PropName Note names may change before release of W3C recommendations

23 RDF Example Example of Dublin Core metadata in RDF John Smith John’s Home Page

24 Browser Support for RDF Mozilla (Netscape's source code release) provides support for RDF. Mozilla supports site maps in RDF, as well as bookmarks and history lists See Netscape's or HotWired home page for a link to the RDF file. Trusted 3rd Party Metadata Embedded Metadata e.g. sitemaps Image from

25 RDF Conclusion  RDF is a general-purpose framework  RDF provides structured, machine- understandable metadata for the Web  Metadata vocabularies can be developed without central coordination  Role for eLib projects in defining schemas?  RDF Schemas describe the meaning of each property name  Signed RDF is the basis for trust

26 Distributed Searching Distributed searching important for the DNER (Distributed National Electronic Resource) ROADS prototype provides cross-searching using whois++ AHDS prototype provides cross-searching using Z39.50

27 Distributed Searching Issues Providing access to resources by software rather than by humans raises several issues: Loss of visibility of service / value-added web services Possible performance problems Information overload Finding the service Solutions: Giving visibility and pointers in results sets Service metadata: –Service only available for cross-searching by non AC.UK users outside peak hours Need for agreed metadata standards (profiles, rights issues, …)

28 Collection Description Work Collection Description Group: UKOLN involvement in producing list of attributes for collection level description (in the library, museum, archival sense), which includes databases of Internet resource descriptions such as SOSIG. Work of interest to clumps and hybrid libraries. WG membership: Dan Brickley (ROADS), Andy Powell (ROADS), Matthew Dovey (Music Online, MALIBU), Verity Brack (RIDING), Dennis Nicholson (BUBL/CAIRNS) and David Kay (FD) See Collection Description eLib supporting study due out in Oct. Will define attribute set (cf Dublin Core)

29 Relevant Protocols Number of formats and protocols could be used to implement distributed searching: Z39.50 ISO standard. Well-known in library world, but heavy-weight whois++ Lightweight IETF standard. Used in several ANR gateways, but not widely deployed LDAP Lightweight version of X.500 directory service. HTTP/NG? Opportunity to develop new solution using object- oriented technologies based on above experiences?

30 Protocols & Collections Which formats and protocols are relevant to collection descriptions for use by software developers? XML: Structured data formats should be based on XML - W3C RDF: All metadata applications should be based on RDF - W3C IETF WebDav: Requirement for distributed authoring include author metadata and collection definitions.

31 IETF WebDav WebDav: Web Distributed Authoring and Versioning An IETF Application Area Relevant proposals: –"WebDAV Advanced Collections Protocol" –"Requirements for Advanced Collection Functionality in WebDAV " –"Requirements for DAV Searching and Locating" See and

32 How Metadata Could Be Used Database Description Music resources, including... Policy (Terms & Conditions / Resource and Service) For licensing reasons, access is restricted to authorised HEIs For performance reasons, access restricted to UK HEI between The service logo must be included in results set, unless results only come from service Permission for cross-searching restricted to other eLib projects You're only allowed to link to the main entry point Individual Give me HTML or PDF resources, not Word, … I'm blind. Include ACSS in results and deliver a sitemap Client Software My browser doesn't support XML,so send me HTML

33 Deployment Models Today integration with cross- searching services uses technologies such as CGI on top of HTTP. It is difficult to provide rich functionality, due to the simplicity of HTML and HTTP. HTTP/NG may provide closer integration between applications and the web. NOTE need for open authentication system (public key infrastructure / DSig?) Web server Distributed Searching Loose integration Web Server Z39.50 server RDF defn. Explain database whois++ server Centroids

34 What's Needed? In order to deploy distributed cross-searching in an open, application-independent way we need: Metadata in a machine-readable format - RDF Syntax for describing the metadata - see RDF pages at Language for processing metadata - see XML-QL, A Query Language for XML at An open authentication infrastructure Issues: TimescalesCosts Software supportProtocol support Short-term pragmatic solution vs long-term purer solution

35 Authentication Deployment of an open, scaleable, flexible authentication system is difficult & expensive Current solutions include: Server-based username and password schemes IP-based schemes Athens - Based on replicated Sybase application See W3C DSig work - Digital Signatures Initiative. See Other Public Key developments - e.g. reports of Post Office involvement, statements from Tony Blair, EU,.. "In May 1998 the Commission published its proposal for a "European Parliament and Council Directive on a Common Framework for Electronic Signatures" (COM(1998)297)."

36 Certificates Should we be looking into using commercially- supported digital ids, such as Verisign's? Can purchase server ID for $349 End user certificates available

37 Browser Support Browsers such as IE provide support for certificates: Use certificates to positively identify yourself, certificate authorities and publishers Trust sites, people and publishers with credentials issued by the following Certifying Authorities You have designated the following software publishers and credential agencies as trustworthy. Windows software can install software.. certified by these publishers with asking you first

38 Using Digital Keys Diagram taken from a Versign White Paper Client initiates a connection Server responds, sending the client its digital ID. The server might also request the client's digital ID for client authentication. The client verifies the server's digital ID. If requested the client sends its digital ID in response to the server's request. When authentication is complete the client sends the server a session key encrypted using the server's public key. Client hello Server Digital ID Client Digital ID Server Once a session key is established, secure communications commence between client & server Session Key

39 Authentication & EU A search for "digital signature" at provided interesting hits: DTI Briefing Paper on "Encryption and Digital Signatures" at European Internet Forum Policy Papers at "Towards A European Framework for Digital Signatures And Encryption" at Will we see development of an open authentication infrastructure funded through Fifth Framework? See

40 Further Information Further Reading: Microsoft Security Advisor at JISC Reports at WWW Security FAQ at

41 Intermediaries can provide functionality not available at client: DOI support XML support Format conversion Intermediaries can provide functionality not available at client: DOI support XML support Format conversion Deployment Issues More sophisticated deployment techniques can be adopted to overcome deficiencies in simple model HTML resource browser Web server Web server simply sends file to client File contains redundant information (for old browsers) plus client interrogation support HTML / XML / database resource browser Server proxy Client proxy Original Model Sophisticated Model Intelligent Web server Example of an intermediary

42 Conclusions To conclude: Standards are important, especially for national initiatives, such as eLib Proprietary solutions are often tempting because: –They are available –They are often well-marketed and well-supported –They may become standardised –Solutions based on standards may not be properly supported by applications Metadata is an important new protocol area Metadata work to support distributed searching is beginning Intermediaries may have a role to play in deploying standards-based solutions

43 Question Time Any questions?