I have no idea why so many are so obsessed about this adding and subtracting public key thingy. Maybe I know nothing much about it and makes me think that way. This adding/subtracting method in my opinion are totally different from Pollard Kangaroo idea or BSGS. From my understanding, by adding/subtracting public key, you can generate a bunch of valid public key, nothing wrong about it. But if 1 private key matching only 1 public key(of course it does), then where is the difference between adding/subtracting and private key bruteforcing? IMHO, it doesn't eliminate any possible private key combination at all. Please correct me if I am wrong.