the short answer = resources. What darkcoin does can be broken with enough resources (massive analysis efforts and masternode control etc).
IMO, it hasn't been attacked because there is no incentive yet. No one has actually done anything with it yet that would warrant an investigation from law enforcement agencies.
Resources as in deep pockets. You have to buy a lot of DASH/DRK to secure a good percentage of the 2300 masternodes in operation (it's about $5k per masternode today), and you'll drive up the price almost surely. Then, while you attack the network as a nefarious masternode (presumably by analyzing traffic and exposing Dashsend mixes) you'll sacrifice your investment, if only for a while. To what end? Most likely, just to demonstrate a vulnerability. Since it's software that runs on a 2-tiered network, you'll just cripple the features provided by the second tier (Dashsend and Instant-X) while the Bitcoin-based blockchain keeps humming along. Meanwhile the developers fix the software and roll it out to the network, which typically reaches supermajority with the latest version within about 6 hours. Note that this has already happened a few times when masternode authentication and payment enforcement had some vulnerabilities that were corrected.
So please, I relish the thought of someone doing this, because in the long run it will serve to harden the DASH network.
I really don't get this argument. 2300 * 5k = $11.5 million. Woopity friggin doo. A drop in the bucket for any government, if they went this route (as opposed to just getting amazon or whatever server to shutdown services). You write as if the ones that would launch such a network attack are the same ones that are pushing forward the frontier of decentralization / new money. You write as if the ones hoping to bring down the network are the same ones trying to wrestle control of our valuation systems from oligarchies / aristocrats / silver spoon / whatever. Comments like these make me realize that some people really don't understand what is going on with cryptocurrencies, or they did at one point and they've forgotten the dream.
As a new observer, what I see happening with all of these scams (paycoin is a big one) is everyone else on this frontier is looking over and going "woooh dude. what the heck are you doing? Come on - we've got serious stuff to do!". The concern (and the subsequent concern trolling) with darkcoin, in this metaphor, is that there are people building a bridge over the fungibility / privacy canyon in this new frontier, but they're not bridge engineers. And down the way, there are others building bridges - and great! More bridges the better, right? But people are going "wooh dude - you probably shouldn't build your bridge that way" and instead of providing any sort of in-depth response, all of the people waiting for that bridge to be built are just like "naw, it'll be fine!!! You don't know what you're talking about." Its often commented that the monero devs are out there spreading fud or wasting time concern trolling as opposed to developing their coin. First, WTF? We're all in this together! Second, I'd rather see a dev addressing questions or quelling concern - these are the ones that know how to build bridges! I'd love to see an actual response from a darkcoin dev of substance! The closest we got was:
https://bitcointalksearch.org/topic/drk-copy-of-evil-knievels-darkcoin-is-not-anonymous-moderated-for-clarity-979315and the darkcoin dev left it with: "ok, you build that python script".... so the goddamn bridge engineer hasn't even run the stress tests himself?
I aint walking over that bridge.
And these are my opinions. I don't speak for monero. I like monero because these are the things I believe.
https://www.youtube.com/watch?v=jVygqjyS4CA