I have read this article on forbes claiming that deepnet has only 7100 onion sites and took only 3 hours to scan completely.
Which to me sounds like total nonsense since if average .onion address is 16 long (example: http://3g2upl4pq6kufc4m.onion/) and can be made up from numbers and letters
Then possible combinations are
65536*(27+10)^16 = 8.0855118e+29 (
ports *(letters + numbers)^symbol_count) which if they would scan 65536 addresses per second (they would need to wait at least one second for response my understanding is that one can only open 65536 connections per machine simultaneously) to scan entire range of addresses they would need
3*60*60*65536 = 707788800 (
hours*minutes*seconds*connections_scanning_at_one_time) They would need
(65536*(27+10)^16)/(3*60*60*65536) = 1.1423622e+21 machines, which I doubt they have.
Could they have made a scan of all the
.onion websites in 3 hours?
I have first asked this question on SO skeptics, but it was suggested that it better fits here.
One of comments was that limitation of 64k simultaneous scans does not apply, still amount of possible addresses is astronomical.
You might want to have a look at programs like zmap, which is the fastest way of scanning things (no 64k connections limitation). Another approach to estimate a minimal time would be to take the data needed for a proper handshake and multiply and then divide by the fattest line you have available. – PlasmaHH