http://yw7nc56v4nsudvwewhmhhwltxpncedfuc43qbubj4nmwhdhwtiu4o6yd.onion/t/the-cyphernomicon-1994/95
I haven’t done this calculation, and won’t here, but the result would likely be something along the lines of X joules of energy that could be harnessed for computation, resulting in Y basic primitive computational steps. I can then find a modulus of 3000 digits or 5000 digits, or whatever, that takes more than this number of steps to factor.