Tor can tunnel any protocol, including IPFS. The normal IPFS network and the Tor IPFS network can't really interface without nodes bridging the gap by speaking both protocols. There are a few PoCs out there for adding Tor support to IPFS.
Tor2web makes the claims a little suspicious, but technically speaking the system could work.
Now that Veilid is out (https://veilid.com/), that seems like a much better base to build a messenger on top of, but it probably doesn't support the IPFS features this thing requires. Maybe a v2 can use it to get the privacy features it needs.
Tor works on top of TCP so it can’t tunnel UDP traffic. Lots of P2P things (like torrents) support both UDP and TCP, some only UDP. If you try to torrent and only have TCP you won’t be able to connect to other peers using UDP.
IPFS can actually run quite well over Tor, and you don't have to use IPFS on a big global network for it to be useful.
We've modified the libp2p WebSocket transport to connect exclusively over Tor to Tor onion services, and we give every Quiet community (like a Discord "server" or Slack workspace) their own IPFS network. Since Tor v3 onion addresses are unguessable, this creates a nice outer security boundary around each community.
As others in the thread have pointed out, the disadvantage of not using a global IPFS network with "pinning services" etc. is that if no one else in your specific community is online, asynchronous message delivery will be disrupted. That said, I believe the privacy benefits are well-worth it.
IPFS is also much more performant when running on networks of a few hundred or thousand users, as opposed to the big global network, so that's another nice thing about the approach we've taken, in addition to the privacy benefits.
I can't tell you how they've implemented it, but OpenBazaar has a Onion transport implementation of IPFS that seems to work. It's not as simple as "glue Tor to the IPFS port and hit go", of course.
TCP DHTs may not be efficient, but efficiency isn't one of IPFS's strengths anyway, in my experience.
Private IPFS networks for each Quiet community make this not a problem. I haven't investigated using Tor on the big global IPFS DHT, but we don't have to worry about that.
Tor2web makes the claims a little suspicious, but technically speaking the system could work.
Now that Veilid is out (https://veilid.com/), that seems like a much better base to build a messenger on top of, but it probably doesn't support the IPFS features this thing requires. Maybe a v2 can use it to get the privacy features it needs.