7 ms·

Why the funny domain name? Is there any technical reason why they cant use protonmail.onion?

by lazyeye 10y ago

pfg 10y ago
Hidden service addresses are not just regular domain names resolved via DNS, they're actually a hash of the hidden service's private (edit: public, see below) key. The fancy onion addresses out there (like Facebook's) were generated by doing a whole lot of brute-forcing to find a key that looks cool.
- bilkow 10y ago
  Aren't the adresses hashes of the _public_ key? Hashes of the private key doesn't make much sense to me, as clients never come to know them. Edit: Grammar
  - pfg 10y ago
    Yep, that's right, thanks. The public key is, of course, calculated based on the private key (these are RSA keys), hence why the brute-forcing still involves the private key, but it's not a hash of that key.
xkxx 10y ago
> Is there any technical reason why they cant use protonmail.onion? Sure, there is. You can read about it in the Tor Phishing Resistance section of the article. > Onion site addresses are 16-character hashes of encryption keys that typically look like this: 3ens52v5u7fei76b.onion. The problem is that there is no good way to differentiate between 3ens52v5u7fei76b.onion and 3lqpblf7bsm532xz.onion, as to the human eye, both are equally unrecognizable. This opens up a phishing risk because a phishing site can trivially be created and unless the 16-character random URL is checked carefully each time, users cannot be certain they are visiting the correct onion site. From a usability standpoint, it is not really realistic to expect users to perform this check every single time. > To bypass this problem, we used ProtonMail’s spare CPU capacity to generate millions of encryption keys and then hashed them, using a “brute force” approach to find a more human readable hash for our onion address. The end result, after expending considerable CPU time, is the following address which is much more resistant to phishing: protonirockerxow.onion as it can be easily remembered as: proton i rocker xow
- lazyeye 10y ago
  Cheers. Thanks for the detailed explanation.

Why the funny domain name? Is there any technical reason why they cant use protonmail.onion?

by lazyeye 10y ago

Why the funny domain name? Is there any technical reason why they cant use protonmail.onion?

pfg 10y ago

Hidden service addresses are not just regular domain names resolved via DNS, they're actually a hash of the hidden service's private (edit: public, see below) key. The fancy onion addresses out there (like Facebook's) were generated by doing a whole lot of brute-forcing to find a key that looks cool.

bilkow 10y ago
Aren't the adresses hashes of the _public_ key? Hashes of the private key doesn't make much sense to me, as clients never come to know them. Edit: Grammar
- pfg 10y ago
  Yep, that's right, thanks. The public key is, of course, calculated based on the private key (these are RSA keys), hence why the brute-forcing still involves the private key, but it's not a hash of that key.

xkxx 10y ago

> Is there any technical reason why they cant use protonmail.onion? Sure, there is. You can read about it in the Tor Phishing Resistance section of the article. > Onion site addresses are 16-character hashes of encryption keys that typically look like this: 3ens52v5u7fei76b.onion. The problem is that there is no good way to differentiate between 3ens52v5u7fei76b.onion and 3lqpblf7bsm532xz.onion, as to the human eye, both are equally unrecognizable. This opens up a phishing risk because a phishing site can trivially be created and unless the 16-character random URL is checked carefully each time, users cannot be certain they are visiting the correct onion site. From a usability standpoint, it is not really realistic to expect users to perform this check every single time. > To bypass this problem, we used ProtonMail’s spare CPU capacity to generate millions of encryption keys and then hashed them, using a “brute force” approach to find a more human readable hash for our onion address. The end result, after expending considerable CPU time, is the following address which is much more resistant to phishing: protonirockerxow.onion as it can be easily remembered as: proton i rocker xow

lazyeye 10y ago
Cheers. Thanks for the detailed explanation.