Overview#Schannel SSP is a Security Support Provider as used in the Microsoft Active Directory Security Support Provider Interface
Schannel SSP is used for access to web-enabled services, such as mail or personal information served on Web pages.
Schannel SSP, which includes a suite of four authentication protocols, uses Public Key certificates to authenticate parties. When authenticating parties, Schannel SSP selects one of the four protocols in the following order of preference:
- Transport Layer Security (TLS).
- Secure Socket Layer (SSL) version 3.0.
- Private Communications Technology (PCT). PCT is disabled by default in Windows Server 2003.
- SSLv2 version 2.0.
The protocol that is selected is the preferred authentication protocol that both parties can support. For example, if a server supports all four Schannel protocols and the client supports only SSL 3.0 and SSL 2.0, the Schannel SSP will use SSL 3.0.