4 Now using a big integer calculator for example
http://www.javascripter.net/math/calculators/100digitbigintcalculator.htm ( I am also using it ) divide the decimal string of hash160 by decimal version of private key
5.The resulting string now You have to multiply times decimal private key.
6 That multiplication will result with a long string of course but quite similar with the first digits like so basically that string will be required by me.
That is pretty obvious that having only hash160 string we cannot see the private key directly can we?
Actually yes you can.
Guys, he's simply factorizing the number at step 6, which is a multiple of the private key.
Since the private key is a known divisor of the hash, it's basically instant to try out all possible combinations of the factors as a private key, hash it, check if for similarity.
Even faster if we know the range of pvt key - filter most of the factor combinations products even before multiplying.