Web Services Enhancements 3.0 July CTP for Microsoft® .NET (WSE) is an add-on to Microsoft Visual Studio® 2005 and the Microsoft .NET Framework 2.0 that enables developers to build secure Web services based on the latest Web services protocol specifications.

WSE 3.0 has significantly simplified common security exchange patterns by providing build-in standard "turnkey" security scenarios to easily secure messages between a client and a service. In WSE 3.0 the Policy format has been simplified to reflect these turnkey security scenarios. Like WSE 2.0, WSE 3.0 enables developers to use declarative files to specify behavior, including security requirements, when receiving and sending messages from a client or a service. These message level behaviors, defined through policy files, are called policy assertions. WSE 3.0 has aligned the declarative policy model with the imperative programming model; such that policies are always used to apply security and other assertions to a SOAP message either via policies files or in code. Policy files can now be associated with a client proxy or a service via a Policy attribute i.e. in C# [Policy("ServerPolicy")]

In addition to an enhanced policy framework, WSE 3.0 provides support for ASP.NET Web services hosted outside of IIS and the ability to send large amounts of binary data efficiently and securely via the W3C SOAP Message Transmission Optimization Mechanism (MTOM) specification. Additional security features include signature confirmation, opaque security tokens and the ability to explicitly create encrypted key tokens. Session management has improved by enabling secure conversations that have been lost to automatically be re-established and explicitly cancelled. This ability also enables secure conversations to be used in web farm scenarios.