As a result, an XSD document can be established to automatically deny them  access  before  any  true  processing  ensues.  Also,  the  unauthorized individual has no idea what type of string the method is expecting. The viewer of the exposed Web service is left wondering if the expected input is a number, a serial code, alphabetic characters, XML, or something else. In addition to this, using a single string parameter in your Web services input  parameter  can  also  keep  the  expected  information  disguised.  By exposing a list of parameters, you could be giving away your business to your competitors. After all, if your competitors are aware of what data you are capturing they might be able figure out the services you are providing, making it easy for them to replicate the Web service and reduce the income that you are generating from your customers. Summary In this chapter we defined SOAP, provided examples demonstrating the protocol hierarchy, and discussed how things were done prior to the exis- tence  of  Web  services.  We  discussed  the  lineage  of  SOAP,  Web  services versus DCOM and Winsock, the SOAP Toolkit, the pros and cons of SOAP- based Web services, what entities should use Web services, high-level .NET Web services security, plus additional security measures that you can use to make your applications more secure. More importantly, we also discussed the reasons behind XML Web ser- vices and why they are an excellent choice for implementing remote invo- cation requirements. We also discovered what types of problems are suited to Web services and presented a brief introduction to Web services in .NET. What Are Web Services? 17