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Security

This section is about security in ZeroNet. If you are not interested in this or don't understand much, just remember a few things and skip this part.

  • Each zite has a public key and a private key. You access ZeroHello by visiting http://127.0.0.1:43110/1HeLLo4uzjaLetFx6NH3PMwFP3qbRbTf3D/ - here, 1HeLLo4uzjaLetFx6NH3PMwFP3qbRbTf3D is a public key. Only site owner has private key, and he publishes changes using it.
  • When you want to download a zite, you connect to other peers you know and download zite content from them.
  • No one can change any data on zite without a private key for that zite.

Wrong SHA512

In ZeroNet, everybody hosts zites, but not all - only the zites they want. For example, if Windows hosts ZeroMe, and iPad wants to download it, iPad connects to Windows directly and says:

  • iPad: Hey, Windows, give me content.json of ZeroMe.
  • Windows: Here it is: ...
  • iPad: Thanks! And I also need index.html, js/all.js and css/all.css of ZeroMe.
  • Windows: Here is index.html: ... But I have no js/all.js and css/all.css, sorry.

Windows gave iPad index.html, but where can iPad find js/all.js and css/all.css? From other peers Windows knows. But the problem is, if Windows is malicious, he can only recommend peers that also didn't have those files.

  • iPad: Good bye, Windows.
  • iPad: ...Searching peers...
  • iPad: Hey, MacOS, you have js/all.js and css/all.css of ZeroMe?
  • MacOS: Of course I have! Here they are: ...

But MacOS is a hacker! It gives wrong js/all.js, with an exploit. Boom! Windows has an infected js/all.js!

...In fact, no. Each zite has its public key and private key. Public key example is: 1BewKAyyiMZHY3AjQn65J6f6Rcb9p1h64K. Public key is zite address.

In content.json of any zite, there is an SHA512 of each files and size of each file. MacOS gave iPad a file with other SHA512, so iPad says:

  • iPad: css/all.css is OK. js/all.js... isn't.
  • iPad: ...Adds MacOS to black list...
  • iPad: Good bye, MacOS.
  • iPad: ...Searching peers...
  • iPad: Hey, Linux, you have js/all.js of ZeroMe?
  • Linux: Yes. Here it is: ...
  • iPad: Thanks. Good bye, Linux.

Now iPad has full ZeroMe and can show it to you.

That's how ZeroNet makes data secure with SHA512.

Wrong content.json

Now Linux needs ZeroTalk (its public key is 1TaLkFrMwvbNsooF4ioKAY9EuxTBTjipT):

  • Linux: You have content.json of 1TaLkFrMwvbNsooF4ioKAY9EuxTBTjipT?
  • MacOS: Yes. Take it, please: ...

As we know, MacOS is a hacker. It gives wrong content.json, with wrong SHA512. Linux would ask MacOS for js/all.js, and MacOS would give Linux file with exploit.

  • Linux: Thanks! ...Wait a minute. content.json is signed with wrong key.
  • Linux: ...Adds MacOS to black list...
  • Linux: Good bye, MacOS.

Linux is clever. content.json is signed with private key. MacOS would have to steal private key or bruteforce it. But the latter is practically impossible. And you shouldn't let anybody steal zite's private key.

Signing

Now, we know how data is signed. Only content.json is signed, and all other files are signed using content.json and its SHA512. It means that nothing can be changed without private key, and usual rainbow tables are useless.

Restricted policy

As ZeroNet cannot create a new server for every zite you visit, it creates a single server at http://127.0.0.1:43110/. So, some more security is needed. ZeroNet opens every zite in a restricted <iframe>, so localStorage and some other things can not be used (because some zite would be able to access other zite's data).

ZeroNet also does not let zites escape from <iframe> - a special token is passed to <iframe>, zites use it to communicate with ZeroNet server for some low-level commands. As it changes when you reload the page, bruteforcing wrapper_nonce (the token) is the only way to escape <iframe>.

But how can data be passed to <iframe>? Only with query string. So, there is always a wrapper_nonce parameter in query string. So, if you expect query string be ?a=2, in fact it is ?a=2&wrapper_nonce=e0ccdebc9a804cfd8ac9eaf78a4a03054acbd400ce981219037647922219fbcd.

It is, however, possible to run a zite without <iframe> wrapper by adding the /raw/ before the url, eg.: http://127.0.0.1:43110/raw/1AsRLpuRxr3pb9p3TKoMXPSWHzh6i7fMGi/en.tar.gz/all/index.html, but this way javascript is disabled by Content-Security-Policy.