Topic: [NXT] Vitalik B. confirms the NXT algo is secure. (Read 2830 times)
^that's a good thread
This was posted in a different thread, but here are some comments I made in regards to Vitalik's analysis of the Nxt algorithm:
Thanks for the info and I applaud efforts like this to formalize the consensus problem. My take on what Vitalik has done is that he's defined a term "crypto-economically secure entropy source" and then provided what he claims is a proof that the Nxt algorithm1 satisfies this. But note that even if the proof is correct, and even if the definition of "crypto-economically secure entropy source" is useful, it is still a far cry from convincingly showing that "Nxt is as secure as Bitcoin."
Let's take a closer look: Vitalik specifies that a "crypto-economically secure entropy source" should posses (a) unpredictability and (b) uninfluenceability. In plain words, his definition of "unpredictability" just means that, given enough time, the "state" of the currency system at some finite time in the future cannot be determined with information available in the present moment. Regardless of whether the system became fully unpredictable 10 minutes or 100 years in the future, his condition would be satisfied. Also note that his proof is only valid in the case where p0(60) is non zero, which is not true at least in the trivial case where an attacker is in control of 100% of the active accounts.
His definition for uninfluenceability (I) just says that there's a minimum cost for an attacker to influence the probability of some blockchain event. Even if the cost is very small, and even if the event he's influencing is very significant, his definition would still be satisfied.
His definition for uninfluenceability (II) is confusing to me. He says that an attacker controlling k of the stake should be unable to change the probability of some event to more than p' = p*(1+b) for some constant b. But there's always a constant value of b that would make p' = 100%. Perhaps I'm misinterpretting something, but if an attacker controlled 0.1% of the stake and could influence the outcome 100% of the time, his definition of uninfluenceability would still be satisfied [although such as system would be very influenceable].
Anyways, I'm not trying to be critical of Vitalik's efforts, I'm just pointing out that the results applied to Nxt may not be very significant in terms of Nxt's actual security properties.
1Neglecting the algorithm for how nodes that were previously offline determine the best blockchain out of many valid candidate blockchains upon rejoining the network.
Vitalik may have just done the proof you were looking for for Nxt...
Thanks for the info and I applaud efforts like this to formalize the consensus problem. My take on what Vitalik has done is that he's defined a term "crypto-economically secure entropy source" and then provided what he claims is a proof that the Nxt algorithm1 satisfies this. But note that even if the proof is correct, and even if the definition of "crypto-economically secure entropy source" is useful, it is still a far cry from convincingly showing that "Nxt is as secure as Bitcoin."
Let's take a closer look: Vitalik specifies that a "crypto-economically secure entropy source" should posses (a) unpredictability and (b) uninfluenceability. In plain words, his definition of "unpredictability" just means that, given enough time, the "state" of the currency system at some finite time in the future cannot be determined with information available in the present moment. Regardless of whether the system became fully unpredictable 10 minutes or 100 years in the future, his condition would be satisfied. Also note that his proof is only valid in the case where p0(60) is non zero, which is not true at least in the trivial case where an attacker is in control of 100% of the active accounts.
His definition for uninfluenceability (I) just says that there's a minimum cost for an attacker to influence the probability of some blockchain event. Even if the cost is very small, and even if the event he's influencing is very significant, his definition would still be satisfied.
His definition for uninfluenceability (II) is confusing to me. He says that an attacker controlling k of the stake should be unable to change the probability of some event to more than p' = p*(1+b) for some constant b. But there's always a constant value of b that would make p' = 100%. Perhaps I'm misinterpretting something, but if an attacker controlled 0.1% of the stake and could influence the outcome 100% of the time, his definition of uninfluenceability would still be satisfied [although such as system would be very influenceable].
Anyways, I'm not trying to be critical of Vitalik's efforts, I'm just pointing out that the results applied to Nxt may not be very significant in terms of Nxt's actual security properties.
1Neglecting the algorithm for how nodes that were previously offline determine the best blockchain out of many valid candidate blockchains upon rejoining the network.
Wait for peer review (at least in the community). There's this weird reverence towards certain individuals in this community from people who don't understand shit. Let the experts evaluate and criticize and withhold your opinion until something reaches some sort of expert consensus.
Everyone now-days in crypto see a fucking PDF paper in academic format and treat it like a fucking bible. Speaking from a scientific background I've seen plenty of beautiful looking papers which 'look' like they got a lot of good stuff to say only to be complete and utter bullshit. Too bad this isn't my field of expertise.
Everyone now-days in crypto see a fucking PDF paper in academic format and treat it like a fucking bible. Speaking from a scientific background I've seen plenty of beautiful looking papers which 'look' like they got a lot of good stuff to say only to be complete and utter bullshit. Too bad this isn't my field of expertise.
No scientist's paper is worth shit unless its been "peer reviewed", which means a big gang of experts all need to have checked it out and agreed with it before it gets published. Most scientific journals are peer reviewed and all the papers in them have been checked by a gang of experts beforehand. We need more experts to check out NXT.
What about white papers? Are they typically peer reviewed? I know it's good practice to peer review academic papers published in journals (which is what this one seems to be minus the journal part) but what about white papers?
What about whitepapers? Especially whitepapers! Everything needs to go through a bullshit filter. Right now, this community is young, so it will take some time to build up a bunch of experts with actual achievements to back up their criticisms. Until then, I wouldn't be so on-board with believing the first positive thing you hear about your favorite coin.
Yes, that is the one.
Didn't Sunny King once say that NXT's PoS algorithm was lifted from Peercoin? I'll see if I can find the quote...
EDIT: Found it:
EDIT: Found it:
Quote from: Sunny King
I thought you were the one coded the PoS in NXT. As far as I know at least the first version of NXT's PoS is a direct clone of PPC's with some modifications, appeared lacking a good understanding of the security involved in PPC's PoS. Cunicula instead always wanted a 'hybrid' system involving proof-of-work in security, whereas PPC's security is 100% proof-of-stake.
That said, you are certainly welcome to try some new ideas in the following versions of NXT.
That said, you are certainly welcome to try some new ideas in the following versions of NXT.
He may have begun with a plan of implementing Peercoin's POS but no Nxt release has ever included it. He thought it was flawed due to being able to accumulate coin age with lots of low stakes. I think this is what led to the dev checkpoints in Peercoin. I'll find his quote...
Not the quote I was looking for but it serves the purpose:
Block generation is determined by previous blocks. If you are doomed to generate next block in 3 hours you can prepare a block instantly, but you have to wait for 3 hours before you can reveal it (otherwise it will be ignored by the network). You can build millions blockchains in parallel to find the best one for an attack, but at some point you will need someone else to generate a block (or wait again). Nxt uses a novel PoS algorithm, not the one PPC, NVC and other altcoins do. Nxt doesn't have their flaws.
You mean this quote right?
Alice has 2500 nxts on her account. Last time she found a block 4 days ago. Her money is like a mining rig with hashpower equal to 2500 * 4 = 10000 GH/s.
Bob has 1000 ntx on his account. He was on vacation and hasn't opened his account for 20 days. His money is like a mining rig with 1000 * 20 = 20000 GH/s hashpower.
Each time Alice or Bob opens their account they have a chance to generate a block. More money they have, higher a chance to do it. More time passed since the previous generated block, higher a chance to generate a new one.
Even a small amount can generate a block by accident.
An exchange that holds coins of its customers can afford to provide the service with 0% fee. It will still earn money via block generation.
Bob has 1000 ntx on his account. He was on vacation and hasn't opened his account for 20 days. His money is like a mining rig with 1000 * 20 = 20000 GH/s hashpower.
Each time Alice or Bob opens their account they have a chance to generate a block. More money they have, higher a chance to do it. More time passed since the previous generated block, higher a chance to generate a new one.
Even a small amount can generate a block by accident.
An exchange that holds coins of its customers can afford to provide the service with 0% fee. It will still earn money via block generation.
After thinking about the mining algorithm I came to conclusion that original proof-of-stake used by PPC and NVC is a bit flawed. Bob could accumulate small amounts on different accounts during a long period of time and then attempt a 51% attack. Artificial limits like max 90 days don't seem to work as intended. Nxt will use a different proof-of-stake approach, I need time to nail some details and then I'll post them here.
I thought by "first version", he meant the first release. Upon further examination, it seems that he chose to move away from PPC's model and use his own implementation of PoS before the first release.
Didn't Sunny King once say that NXT's PoS algorithm was lifted from Peercoin? I'll see if I can find the quote...
EDIT: Found it:
EDIT: Found it:
Quote from: Sunny King
I thought you were the one coded the PoS in NXT. As far as I know at least the first version of NXT's PoS is a direct clone of PPC's with some modifications, appeared lacking a good understanding of the security involved in PPC's PoS. Cunicula instead always wanted a 'hybrid' system involving proof-of-work in security, whereas PPC's security is 100% proof-of-stake.
That said, you are certainly welcome to try some new ideas in the following versions of NXT.
That said, you are certainly welcome to try some new ideas in the following versions of NXT.
He may have begun with a plan of implementing Peercoin's POS but no Nxt release has ever included it. He thought it was flawed due to being able to accumulate coin age with lots of low stakes. I think this is what led to the dev checkpoints in Peercoin. I'll find his quote...
Not the quote I was looking for but it serves the purpose:
Block generation is determined by previous blocks. If you are doomed to generate next block in 3 hours you can prepare a block instantly, but you have to wait for 3 hours before you can reveal it (otherwise it will be ignored by the network). You can build millions blockchains in parallel to find the best one for an attack, but at some point you will need someone else to generate a block (or wait again). Nxt uses a novel PoS algorithm, not the one PPC, NVC and other altcoins do. Nxt doesn't have their flaws.
Didn't Sunny King once say that NXT's PoS algorithm was lifted from Peercoin? I'll see if I can find the quote...
EDIT: Found it:
What is so huge in that? Often developers talk about other projects. He even said Monero technology is cool, so what?
I was surprised to see Vitalik talk positively about NXT since Ethereum's features and NXT's features overlap considerably more than that of Ethereum and Monero. NXT is more of a direct competitor to Ethereum than Monero is.
No scientist's paper is worth shit unless its been "peer reviewed", which means a big gang of experts all need to have checked it out and agreed with it before it gets published. Most scientific journals are peer reviewed and all the papers in them have been checked by a gang of experts beforehand. We need more experts to check out NXT.
What about white papers? Are they typically peer reviewed? I know it's good practice to peer review academic papers published in journals (which is what this one seems to be minus the journal part) but what about white papers?
Aren't you a NXT dev? Or are you more involved in the low-level programming side of things? And Vitalik is barely 20. I doubt he has a PhD. He's still probably one of the best in the field though.
EDIT: Found it:
WOW, this is huge people!
What is so huge in that? Often developers talk about other projects. He even said Monero technology is cool, so what?
I was surprised to see Vitalik talk positively about NXT since Ethereum's features and NXT's features overlap considerably more than that of Ethereum and Monero. NXT is more of a direct competitor to Ethereum than Monero is.
Wait for peer review (at least in the community). There's this weird reverence towards certain individuals in this community from people who don't understand shit. Let the experts evaluate and criticize and withhold your opinion until something reaches some sort of expert consensus.
Everyone now-days in crypto see a fucking PDF paper in academic format and treat it like a fucking bible. Speaking from a scientific background I've seen plenty of beautiful looking papers which 'look' like they got a lot of good stuff to say only to be complete and utter bullshit. Too bad this isn't my field of expertise.
Everyone now-days in crypto see a fucking PDF paper in academic format and treat it like a fucking bible. Speaking from a scientific background I've seen plenty of beautiful looking papers which 'look' like they got a lot of good stuff to say only to be complete and utter bullshit. Too bad this isn't my field of expertise.
Wait for peer review (at least in the community). There's this weird reverence towards certain individuals in this community from people who don't understand shit. Let the experts evaluate and criticize and withhold your opinion until something reaches some sort of expert consensus.
Everyone now-days in crypto see a fucking PDF paper in academic format and treat it like a fucking bible. Speaking from a scientific background I've seen plenty of beautiful looking papers which 'look' like they got a lot of good stuff to say only to be complete and utter bullshit. Too bad this isn't my field of expertise.
Everyone now-days in crypto see a fucking PDF paper in academic format and treat it like a fucking bible. Speaking from a scientific background I've seen plenty of beautiful looking papers which 'look' like they got a lot of good stuff to say only to be complete and utter bullshit. Too bad this isn't my field of expertise.
No scientist's paper is worth shit unless its been "peer reviewed", which means a big gang of experts all need to have checked it out and agreed with it before it gets published. Most scientific journals are peer reviewed and all the papers in them have been checked by a gang of experts beforehand. We need more experts to check out NXT.
What about white papers? Are they typically peer reviewed? I know it's good practice to peer review academic papers published in journals (which is what this one seems to be minus the journal part) but what about white papers?
Hmmm...let me think about that one for a moment.
Oh, yeah, that would be down to the complete lack of a PhD in cryptography, (left it in my other suit) or even a basic grasp of the maths involved in VB's paper.
That, old son, is precisely why we need peer review.
Me saying: "Looks fine, mate, she'll be right" is not a solid basis for a system of crypto currency, even if I am completely correct.
Oh, yeah, that would be down to the complete lack of a PhD in cryptography, (left it in my other suit) or even a basic grasp of the maths involved in VB's paper.
That, old son, is precisely why we need peer review.
Me saying: "Looks fine, mate, she'll be right" is not a solid basis for a system of crypto currency, even if I am completely correct.
Aren't you a NXT dev? Or are you more involved in the low-level programming side of things? And Vitalik is barely 20. I doubt he has a PhD. He's still probably one of the best in the field though.
It's a good news that finally a independent people confirm NXT is secure.
it was borned almost one and half a year.
it was borned almost one and half a year.
Too intellectual for me, but good to see an independent compliment for nxt
Hmmm...let me think about that one for a moment.
Oh, yeah, that would be down to the complete lack of a PhD in cryptography, (left it in my other suit) or even a basic grasp of the maths involved in VB's paper.
That, old son, is precisely why we need peer review.
Me saying: "Looks fine, mate, she'll be right" is not a solid basis for a system of crypto currency, even if I am completely correct.
Oh, yeah, that would be down to the complete lack of a PhD in cryptography, (left it in my other suit) or even a basic grasp of the maths involved in VB's paper.
That, old son, is precisely why we need peer review.
Me saying: "Looks fine, mate, she'll be right" is not a solid basis for a system of crypto currency, even if I am completely correct.
But I'm certainly not qualified to make any judgements here.
so Dave, why is that?
or, better yet, do your best to read the paper.....I've gven it a try, and the sections on NXT seem to be generally positive. But I'm certainly not qualified to make any judgements here. Much peer review is what is needed......
No scientist's paper is worth shit unless its been "peer reviewed", which means a big gang of experts all need to have checked it out and agreed with it before it gets published. Most scientific journals are peer reviewed and all the papers in them have been checked by a gang of experts beforehand. We need more experts to check out NXT.
Wait for peer review (at least in the community). There's this weird reverence towards certain individuals in this community from people who don't understand shit. Let the experts evaluate and criticize and withhold your opinion until something reaches some sort of expert consensus.
Everyone now-days in crypto see a fucking PDF paper in academic format and treat it like a fucking bible. Speaking from a scientific background I've seen plenty of beautiful looking papers which 'look' like they got a lot of good stuff to say only to be complete and utter bullshit. Too bad this isn't my field of expertise.
Everyone now-days in crypto see a fucking PDF paper in academic format and treat it like a fucking bible. Speaking from a scientific background I've seen plenty of beautiful looking papers which 'look' like they got a lot of good stuff to say only to be complete and utter bullshit. Too bad this isn't my field of expertise.
No scientist's paper is worth shit unless its been "peer reviewed", which means a big gang of experts all need to have checked it out and agreed with it before it gets published. Most scientific journals are peer reviewed and all the papers in them have been checked by a gang of experts beforehand. We need more experts to check out NXT.
What happened here is that some unqualified people just took their favorite part the parts relevant to Nxt from the paper and present it as FACT Vitalik Buterins opinion.
FIFY
Reread the OP and title.
Wait for peer review (at least in the community). There's this weird reverence towards certain individuals in this community from people who don't understand shit. Let the experts evaluate and criticize and withhold your opinion until something reaches some sort of expert consensus.
For people interested in knowing more about the peer to peer and line by line review of Nxt code - https://bitcointalksearch.org/topic/nxt-source-code-flaw-reports-397183
by the way, most of devs who participated in the Nxt code review had started to create their own Nxt like PoS cryptos after the reviewing. Nxt original code has become a school, which alone is a huge contribution to the crypto society.
What I meant was a bit more meta than just evaluating NXT directly. In fact, it's evaluating the evaluation... So someone to criticize Vitalik's paper, either in a good way or bad way is the way to go here. As the community evolves, I hope we will have more of this in the future.
Just saying that unconditional 'trust' is especially bad and goes against the whole concept of decentralized currencies. While Vitalik's opinion might be more informed or relevant than another's, it should still be met with the same criticism as a new opinion.
What happened here is that some people just took their favorite part from the paper and present it as FACT.
Just saying that unconditional 'trust' is especially bad and goes against the whole concept of decentralized currencies. While Vitalik's opinion might be more informed or relevant than another's, it should still be met with the same criticism as a new opinion.
What happened here is that some people just took their favorite part from the paper and present it as FACT.
Neither Garzik nor Buterin would be able to peer review or submit anything on a cryptography (or anything computer) peer-reviewed academic database. Vitalik's credentials are even worse than Garzik's, Vitalik's call for fame was editing an obscure magazine read by almost no one and only recently became the mascot of a $18 million vaporware consortium.
That's crypto for you. Even Andreas Antonopoulos has refused to prove his credentials when demanded to by judges. It'll be a popcorn moment when an investigative journalist finally goes after Andreas Antonopoulos and they find out he was a hotdog vendor or a starbucks employee before becoming Bitcoin's orator.
What I meant was a bit more meta than just evaluating NXT directly. In fact, it's evaluating the evaluation... So someone to criticize Vitalik's paper, either in a good way or bad way is the way to go here. As the community evolves, I hope we will have more of this in the future.
Just saying that unconditional 'trust' is especially bad and goes against the whole concept of decentralized currencies. While Vitalik's opinion might be more informed or relevant than another's, it should still be met with the same criticism as a new opinion.
What happened here is that some unqualified people just took their favorite part from the paper and present it as FACT.
Just saying that unconditional 'trust' is especially bad and goes against the whole concept of decentralized currencies. While Vitalik's opinion might be more informed or relevant than another's, it should still be met with the same criticism as a new opinion.
What happened here is that some unqualified people just took their favorite part from the paper and present it as FACT.
Wait for peer review (at least in the community). There's this weird reverence towards certain individuals in this community from people who don't understand shit. Let the experts evaluate and criticize and withhold your opinion until something reaches some sort of expert consensus.
Everyone now-days in crypto see a fucking PDF paper in academic format and treat it like a fucking bible. Speaking from a scientific background I've seen plenty of beautiful looking papers which 'look' like they got a lot of good stuff to say only to be complete and utter bullshit. Too bad this isn't my field of expertise.
Everyone now-days in crypto see a fucking PDF paper in academic format and treat it like a fucking bible. Speaking from a scientific background I've seen plenty of beautiful looking papers which 'look' like they got a lot of good stuff to say only to be complete and utter bullshit. Too bad this isn't my field of expertise.
No scientist's paper is worth shit unless its been "peer reviewed", which means a big gang of experts all need to have checked it out and agreed with it before it gets published. Most scientific journals are peer reviewed and all the papers in them have been checked by a gang of experts beforehand. We need more experts to check out NXT.
"Experts" don't even look at Bitcoin or it's only been a small handful. Can't really blame them as Bitcoin is very insignificant in the broad picture: only 250,000 users. There's more people with subscriptions to online dating sites than people using Buttcoin
Wait for peer review (at least in the community). There's this weird reverence towards certain individuals in this community from people who don't understand shit. Let the experts evaluate and criticize and withhold your opinion until something reaches some sort of expert consensus.
Everyone now-days in crypto see a fucking PDF paper in academic format and treat it like a fucking bible. Speaking from a scientific background I've seen plenty of beautiful looking papers which 'look' like they got a lot of good stuff to say only to be complete and utter bullshit. Too bad this isn't my field of expertise.
Everyone now-days in crypto see a fucking PDF paper in academic format and treat it like a fucking bible. Speaking from a scientific background I've seen plenty of beautiful looking papers which 'look' like they got a lot of good stuff to say only to be complete and utter bullshit. Too bad this isn't my field of expertise.
No scientist's paper is worth shit unless its been "peer reviewed", which means a big gang of experts all need to have checked it out and agreed with it before it gets published. Most scientific journals are peer reviewed and all the papers in them have been checked by a gang of experts beforehand. We need more experts to check out NXT.
Let the experts evaluate and criticize and withhold your opinion until something reaches some sort of expert consensus.
Jeff "HashesDoNotMatch" Garzik is the only expert I know. And he already evaluated Nxt. Do you know any other experts?
maybe David Latapie of Munero is a good match
Let the experts evaluate and criticize and withhold your opinion until something reaches some sort of expert consensus.
Jeff "HashesDoNotMatch" Garzik is the only expert I know. And he already evaluated Nxt. Do you know any other experts?
Jump to: