[Tutor] All possible 16 character alphanumeric strings?

[Steven D'Aprano]

Akleider, you didn't include attribution for the person you are quoting,
which is a bit rude and also means I can't be sure who it was. From
context, I *think* it is the original poster Scott:

On 16/09/12 13:06, akleider at sonic.net wrote:
>> I'm using this to write a program I'm calling TORdialer with the goal of
>> attempting to basically ping all possible TOR hidden service pages with
>> the goal of having an absolutely complete list of all TOR hidden services
>> on the net right now.

Did you really think that when a group of really smart security and network
experts sit down to design a protocol for hiding services from discovery,
that it would actually be vulnerable to a programming beginner who just
lists out all the possible sites and pings them? And the TOR designers
didn't think of that?

I'm sorry if this comes across as condescending, but it's kinda cute that
you thought this was viable. TOR is designed to be resistant to discovery
from people with the full resources of the United States and Chinese
governments. Believe me, they already considered the "brute force attack"
where you list out every possible address.

If every person in the world runs their own TOR hidden network, then the
chances of you pinging *even one* by accident is about 1 in 172703688516375.
If your TORdialer program could ping a million addresses per second, you
would need to run it non-stop for over five years just to find *one* address.

"An absolutely complete list"... oh my stars and garters.

(Remember those maths classes on permutations and combinations that you
probably thought were totally pointless? *This* is why they're important.)



-- 
Steven