According to the specs, it has 1kB of ram. You're going to need to be quite clever to implement a working TCP-IP stack and an HTTP server in that.

An RSA key is 4kB by itself, so TLS is out of the picture.

I was also going to suggest that... But I imagine that the Ethernet port or antennae wire (and necessary battery to power antennae) would dwarf the size of that MCU. But thinking again, I suppose if the rules permit the MCU to be directly wired to the Ethernet cable, then could bitbang an early Ethernet standard with this MCU's pins...