1. Web Services Security Challenges
Based on underlying technologies that already have security challenges
Web services complexities pose new potential problems
Concerns with security standards and their adoption by system and component vendors
Overlapping and possibly incompatible standards

2. Web services architectural layers

3. Web services standards
Standards for describing, discovering, and invoking web services
Based on XML
Represent data totally independent of application, protocol, vocabulary, OS, programming language
Described using XML schema
Standards organizational committees:
World wide web consortium (W3C)
Organization for the advancement of structured information standards (OASIS)
Web services interoperability (WS-I) organization
Liberty alliance
Internet engineering task force (IETF)

4. Layers and web services standards

5. Web services security standards
Several security-related specifications for providing security for web Services including:
WS-Security
Web Services Security Addendum
WS-Security Policy
WS-Trust
WS-Secure Conversation
Web Services Security Profile for XML-based Tokens
WS-Federation
WSPL (Web Services Policy Language)
The Liberty Alliance Project
These security protocols can bind to Web services messaging protocols
Designed to be modular and composable, to allow developers to use just the required capabilities
Key to the success of Web services is open standards and interoperability among service providers

6. Layers and web services security standards