Download the SSL/TLS in Windows Server 2003 white paper.

The white paper's extract reads:

The Microsoft® Windows Server™ 2003 operating system supports Schannel, an implementation of three protocols (TLS 1.0, SSL 3.0 & SSL 2.0) that provide network security for applications and services. This paper focuses on the Secure Sockets Layer (SSL 3.0) protocol and Transport Layer Security (TLS 1.0) protocol. These protocols offer certificate-based authentication and secure data transfers using symmetric encryption keys.