How is it that more complex keys are discovered but simpler one like 64 have not? i would have thought the ones after 64 would be significantly more difficult/nearly impossible. Is there any reason why this is the case?
Every five txs the public key is exposed. Maybe someone find it with other approach.
There is no "approach". The whole point of creating original transaction is to prove it, and it has been proven solid for 6 years since then.
The "approach" that was mentioned is in the different program used. People have used the "Kangaroo" program to find the keys with known public keys; versus brute force approach for the smaller ranges, i.e. 64 bit range.
The thing is that you can't use the Kangaroo "approach" to the small ranges because their public address are not known.
We are all wondering which was the privkey 