As a non statistician or economist I have my own critique to this paper, and I get the feeling it is trying to ride the waves of bitcoin, but the system is not completely understood, or it is riding the waves of big blockers. It starts at the very beginning with a phrase like this:
Bitcoin is an electronic payment system that relies on a combination of cryptography and a large, anonymous, decentralized collection of participants, called miners, to verify transactions, without the need of any trusted third party.
The role of non mining (full) nodes is not covered here... without the relaying nodes an important part for the security of the bitcoin eco system is missing in the equations (remember last year, when miners wanted to have 2mb blocks, and UASF prevented this?)
Further down the text we are informed about a misnomer:
while this problem is called the “double spending” problem, the “double” part is a misnomer — the attacker can re-spend his Bitcoins arbitrarily many times.
WoW! Hats off! Fantastic, for an economic paper on bitcoin we learn s.th.about the usage of the word « double ». What do these guys think they are?
Next quote:
In words: the equilibrium per-block payment to miners for running the blockchain must be large relative to the one-off benefits of attacking it.
Who would have guessed it? So the creation of the word « per block payment equilibrium » is no misnomer, and economical incentive to drive an attack must be way higher than the block rewards? Is this the essence of the paper?
Equation (3) places potentially serious economic constraints on the applicability of the Nakamoto (2008) blockchain innovation. By analogy, imagine if users of the Visa network had to pay fees to Visa, every ten minutes, that were large relative to the value of a successful one-off attack on the Visa network.
Doesn’t this smell like big blocker arguments? This continues on page 8, where a 30% tax is derived. Funny.
Further on page 11 we find several attack scenarios, with varying assumptions. At the end follows a conclusion which states that decentralized trust is ingenious, but expensive. Followed by a derivation, that a high level of trust requires high running costs of the blockchain relative to the amount for attacking the system. As if the scenarios haven’t been discussed up and down in the relevant forums.
The whole paper relies on some mathematical models, which are based on someone’s imagination, and achieve a certain level of complexity. Ok. But the assumptions haven’t been checked against any period of the ten years history of blockchain, e.g. why was blockchain not attacked? How is blockchained secured by technological progress through history? What is the incentive model for the attacker at specific periods in time? ... This could proof relevance and applicability of the text... as there is no such thing, it looks like an ivory tower model, that fails to link to reality. And the conclusions are well known facts - blockchain is expensive, and attacking it requires enormous amounts. And the economic limits, as found in the headline, are not calculated. Btw: is it on purpose that Lightning is not mentioned at all? Because it doesn’t fit in the 30% tax model?
I am missing relevance in this text.