You have two alternatives.
One is to use the tls_socket command from TWAPI (which comes with
the magicsplat distribution) instead of the TLS extension.
For example,
(ashok) 1 % package require twapi
4.2.13
(ashok) 2 % package require http
2.8.12
(ashok) 3 % http::register https 443 twapi::tls_socket
443 twapi::tls_socket
(ashok) 4 % set tok [http::geturl
https://www.example.com]
::http::1
(ashok) 5 % ::http::data $tok
<!doctype html>
<html>
....
The advantage of twapi::tls_socket over the TLS extension is that
it uses the Windows certificate store and thus automatically takes into
account new root certificates, expired certs etc. With the TLS extension
on Windows, you need to keep root certs updated yourself by some means
and explicitly check server certs are valid, not expired etc. You may or
may not care :-) The disadvantage of TWAPI is of course that it is
Windows only. (Full disclosure - I am the author of both twapi and the
magicsplat distro).
The other alternative, if you want to stick to the TLS extension, I
believe the BAWT Windows distribution will have what you need. In fact,
it also makes it easy to build the whole enchilada yourself with the
MingW tools.
/Ashok