Interesting paper. Can you spot what they conveniently left out?...

Interesting paper. Can you spot what they conveniently left out? A certain simple fact of algebraic number theory. I'll spell it out: most public keys can be generated by many different private keys. In other words, it is not necessary to solve for the private key actually used to generate the public key to do transactions, but only to solve for a single private key that gives rise to the same public key. The probability of finding such a suitable private key is high in the vast majority of cases.

This is what renders crypto wallets insecure and subject to spoofing. It is intrinsic to the design. It's deliberate.