Overview#PCT requires some context
PCT - Private Communications Technology#Private Communications Technology 1.0 was a protocol developed by Microsoft in the mid-1990s.
PCT was designed to address security flaws in version 2.0 of Netscape's Secure Sockets Layer protocol and to force Netscape to hand control of the then-proprietary SSL protocol to an open standards body.
Schannel SSP supports PCT 1.0 for backward compatibility only.
PCT supports most of the cipher suites supported by SSL 2.0.