USA and China with few billion dollars can bruteforce onion v2 address in days!
And any old non-curve cipher.
>.onion Address | 2^(5*length-1) / hashspeed
> Ebit E10 | 18,000,000 MH/s
>Radeon 6850 301.4
yep, ~59722 times faster on a bitcoin double SHA-256.
for 'unit' it should be 35832780 MH/s.
(AMD Radeon HD6850 600 MH/s on scallion)
With 1 MH/s you need 6996098493141 days.
With 35832780 MH/s you need 195243 days.
(For one unit with ~5500 price at start.)
With 5000 units and roughly ~27,2M $ you can do all job in 40 days.
But there is 25,000 machines!
And states and china definitely can make something for ciphers bruteforce.
With 25K machines you can brute full 16 symbol onion in 8 days.
I think, bruteforce any old non-curve ciphers in ~week for 180M $ worth it
and governments can pay even some billions for that (for complex goals).
600 billion $ for US and ~166 billion $ for china
'Bruteforce facility' very plausible thing.
Thats why v3 address longer and based on elliptic curve cipher.