When you go to a website on the regular internet, the name you type into your URL bar doesn't contain any location information. Instead, you go to a Dynamic Name Server (DNS) server (often run by your ISP) and and get the IP address, which tells your browser where to go.

With Tor, the hashes you see are analogous to the IP in regular internet: they tell your browser where to go. But there's no DNS for Tor, so you can't hide address behind a name.

Incidentally, this story is about SciHub being blocked at the DNS level, meaning that the domain https://sci-hub.io/ was removed from the DNS servers. But it's still available at the IP level at https://31.184.194.81/

This story demonstrates the need for DNS to be decentralized. ICANN has far too much control and is now using it for censorship that holds back the progress of all of humanity.

IANA would have to un-delegate a whole range from RIPE.

I don't see that happening unless they want to fracture the network.

Perhaps Elsevier will be able to force ISPs to blacklist that particular IP, but nothing more.

I also suspect they will move the domain under a ccTLD, not subject to the whims of ICANN.

Facebook managed to get https://facebookcorewwwi.onion/

A simplified version: X % 2 = H

If I give you the formula, and a H of 1, can you, with certainty, tell me that my input was 1029? Cryptographic hashes have a similar property, just with a very large collision space - for Tor only 1 in 36^16 inputs will produce a given hash; yet you still can't guarantee that an input that produces that hash is the original input (and just guessing the possible inputs will take you a very long time).

The downside of our hash above is that it gives you a pretty good clue of what the original input was: if you get an H of 1029 from the forumla X % 10000000 = H, you'll have a pretty good idea of what the X was. Cryptographic hashes do not share this weakness - they will stretch the input, and ensure that there are no clues left as to what the original input was.

TLDR: they are designed to behave that way. Their alternative name is "one-way hash function".

Edit: I'm wrong. It's based on the hash of the public key. But it's rather confusing. After you create an onion service, you get a private key and an onion address. You don't actually get a public key, just the hostname based on it. I suspect that the public key could be found somehow. But it's not used for anything, that I know of.

But, in short: for a name to be useful in a global context, it has to be unambiguous or unique. If there isn't a centralized naming authority / registry, then that means that you can't be able to pick an arbitrary name. (If you could, you could just decide to use the same name as someone else, and now there's no way to figure out which one of you the name indicates.)

Edit: I'm wrong. It's based on the hash of the public key.