i have a thought experiment on SC's. Adam, if you're still out there, i would appreciate your thoughts:
the goal is to theoretically construct a SC that is equal in as many respects to the MC as possible and then predict the vulnerabilities of each. for this, i am going to invoke 2 of the marketing tactics that the SC proponents have claimed to be advantages and givens, are in fact true.
1. that of a firewall btwn the SC and MC that "protects" the MC from any failures or fraud on the SC.
2. that the destruction of scBTC can only result in an increase in the price of BTC on MC.
we will use the op_spv as the model along with its 2 day 2wp clearing mechanism. 50% of all BTC will be on the MC and the other 50% BTC (scBTC) will be on the SC. there is perfect 100% MM'ing of the SC. the fiat exchange prices are equal. the only apparent difference is that the SC has an innovation beyond the capability of Bitcoin which attracted usage in the first place.
is this an equilibrium situation that is stable? imo, no.
what has become clear over the last 6 yrs of Bitcoin mining is that even when an individual mining pool has gained close to or even exceeded the 51% hashing market share required to elicit a 51% attack, they have refused to do so. we have seen 3 examples of this: Deepbit, BTCGuild, and Ghash.io. i have explained this somewhat unexpected behavior (to some) in terms of the Nash Equilibrium which states that it would be in the attackers unfavorable self interest to attack the MC in that the immediate result would be to kill confidence in Bitcoin along with the price. such a strategy would even likely be unprofitable as any short position or sale of stolen Bitcoin would be unavailable as exchanges would halt the attackers ability to cash out in any meaningful size on such a scheme. also, the attackers would sacrifice the millions or so in hardware they were forced to expend initially, not to mention the time and labor required to set up such an operation. so, in this sense, there is a severe if not catastrophic negative economic consequence to attacking the MC. this is nothing new to those of us who've been around for a while.
thus, i submit over the long run that in the theoretical construct made above with a SC involved, the MC would still not be attacked given the above game theory as it would amount to self destruction. what about the SC? the attacking miner, or coalition of miners, know that there is a firewall that will prevent any negative feedback effects back to the MC, at least, in terms of the protocol functioning. and they will believe any attack that results in destruction of scBTC will only drive up the price of BTC on the MC. there will be no negative economic consequences for the attack on the SC that feedback to the MC. thus, i submit an attack is an inevitable consequence. and this would be the lower bound expectation of benefit for the attackers. the upper bound would include other economic inducements which aren't necessary to make my argument. those being:
1. attackers could place a large fiat short position in place on a derivatives exchange to benefit from a scBTC price crash from an all out SC failure.
2. they could try to immediately sell stolen scBTC.
3. they could be attackers who were not allowed to mine the SC because of illegality enforced by its gvt and thus benefit by destruction of this competing SC.
but my point is not to compare the upper bound economic benefits of financial gain of such an attack. it is simply to illustrate that the lower bound minimal benefit or expectation, is that there are no negative economic consequences for the attackers and is enough, by itself, to expect an eventual attack. one could try to argue that a coalition of miners would not want to destroy 50% of their tx fee volume on the SC. but to this, i would say that, at the very least, the 3 above economic inducements would be enough to neutralize this argument.
i believe this concept of economic self preservation allows us to compare the economic viability of SC's of tomorrow to the overwhelming evidence that makes a 51% attack on the MC an extremely low risk event today: a reluctance to destroy one's own business or seed corn.
have at it.