[ac29]

The main page [0] and main download [1] are HTTPS. GPG signatures are provided as well.

[0] https://www.chiark.greenend.org.uk/~sgtatham/putty/latest.ht...

[1] https://the.earth.li/~sgtatham/putty/latest/w64/putty-64bit-...

[lostmsu]

That probably changed just recently.