Project reached somewhat usable state. Check it here.
SChannel is Windows built-in implementation of TLS protocols. This allows supporting secure connections without any external library.
Repo contains:
unit with transport-agnostic helper functions for easy implementation of TLS communication by means of Windows SChannel.
sample of transport-agnostic synchronous TLS handshake using callback functions for real communication
API declarations borrowed from JEDI project
ICS TWSocket descendant that performs TLS communication
demo project for performing any textual (mainly HTTPS) requests via secure connection
Note. I first started learning what TLS is a couple of weeks ago :) So units contain only a necessary minimum to interact with TLS server. Certs and other advanced stuff are in TODO.
Thanks to author of TLS-Sample from http://www.coastrd.com/c-schannel-smtp and JEDI for WinAPI headers.