[t90fan]

> Aside from the whole, well... lack of HTTPS support in any browser you could possibly use on that OS. Also in Win95. And Win98. But regardless...

Use a proxy running on your LAN.

The proxy connects to the site over modern HTTPS (i.e. TLS 1.2 or whatever) and you connect to the proxy over plain HTTP, or whatever old version of HTTPS your client supports (NT4 sp6 with IE6 supports TLS1.0 or SSL3, as the latest, dunno about win 98), if you make sure to trust its cert.