Re: [bitcoin-dev] MAD-HTLC

2020-06-30 Thread Tejaswi Nadahalli via bitcoin-dev
Hello ZmnSCPxj (as there would be no better way to start an email to you :-), I posted a reply to Dave in the other sub-thread of this main thread. We have a paper about something similar to what you have said - where we look at "weak" and "strong" miners, and how even if there are a few weak

Re: [bitcoin-dev] MAD-HTLC

2020-07-02 Thread Tejaswi Nadahalli via bitcoin-dev
On Wed, Jul 1, 2020 at 6:58 PM ZmnSCPxj wrote: > And your paper posits that if a miner is weak, its best strategy is to > take the myopic strategy and include the currently-valid Alice transaction. > Yes. The proof is quite trivial and follows from the definition of weak: if the myopic miner's

Re: [bitcoin-dev] MAD-HTLC

2020-07-02 Thread Tejaswi Nadahalli via bitcoin-dev
On Wed, Jul 1, 2020 at 6:58 PM ZmnSCPxj wrote: > Another analysis, similar but a little off-tangent to yours, would be to > consider miners as a breeding group with various strategies, and see which > one is able to gain more utilons (with which it creates more miners) and > outbreed the other

Re: [bitcoin-dev] MAD-HTLC

2020-07-06 Thread Tejaswi Nadahalli via bitcoin-dev
On Fri, Jul 3, 2020 at 1:49 PM Itay Tsabary wrote: > Note the required token amount for the collateral contract is low and > independent of the required deposit tokens -- only a relatively small > incentive is required to make "acting honestly" Bob's preferred choice. > So, this is basically a

Re: [bitcoin-dev] MAD-HTLC

2020-07-03 Thread Tejaswi Nadahalli via bitcoin-dev
On Thu, Jul 2, 2020 at 6:06 PM ZmnSCPxj wrote: > At fee spikes, this x will go higher, and thus (f - x) / (b - x) will be > far smaller than f / b and might even become negative, in which case the > Alice transaction will not be confirmed even by myopic miners, because the > Alice transaction

Re: [bitcoin-dev] MAD-HTLC

2020-07-03 Thread Tejaswi Nadahalli via bitcoin-dev
On Fri, Jul 3, 2020 at 12:17 PM ZmnSCPxj wrote: > > > In fact, one rule of thumb might be that wherever watchtowers are > required, a timelocked bribe might be possible. > > I think a better heuristic is that, if the logic of the construction > assumes "transaction with earlier locktime

Re: [bitcoin-dev] MAD-HTLC

2020-06-29 Thread Tejaswi Nadahalli via bitcoin-dev
On Sun, Jun 28, 2020 at 2:16 PM David A. Harding via bitcoin-dev < bitcoin-dev@lists.linuxfoundation.org> wrote: > So, if I understand correctly, even a small amount of "myopic" hashrate > and long timeouts---or modest amounts of hashrate and short > timeouts---makes this attack unlikely to