Microsoft Web Services Enhancements 3.0

Microsoft's Web Services Enhancements (WSE) is an add-on that allows to develop secure web services. WSE is capable of implementing digital signatures and encryption for services. Among other capabilities, it logs in credentials, policy-driven web services.
The add-on requires you to have .NET Framework 2.0 or Visual Studio 2005. Once this is installed, you have at your disposal the Certificates and the Configuration tools. This allows you to setup and configure what kind of security a web service is going to have. You can choose how you build a certificate and how strong the encryption will be.
WSE also includes, what Microsoft calls, Turnkey Security Assertions. This is a series of rules that handles security in different scenarios. The rules can be configured by the developer for the security to work properly. WSE also includes SOAP message Transmission, which allows to secure binary transfers.
If developers want to have their web services secure, WSE is definitely the tool for them to use.