I've spotted same things before. https://bt.irlbtc.com/view/1031953.msg11136641#msg11136641
What's really happening, I really wanna know.

This makes sense, although I understand that nounces are exhausted pretty kickly. I see no reason why they should restrict nounces. It requires more computation to change extranounces for example. Obviously I can accept that this is an implementation improvement of mining for which we do not have the precise details.


I also observe that the last 3 blocks are by anonymous miners. Thus if it is the same miner he is trying to conceal his identity, so we should assume that it is the same hardware. It is curious that suddenly the same hardware solves the block in such a short timeframe. It is of course possible.  Just inspecting mined blocks there is a high clustering of anonymous miners. It will be interesting to do a statistic on this also.

~20% of the network hashing power is done by unknown miners. Why would you assume they are using all the same hardware? A complete non sequitur.

It was the observation of gmaxwell because of the clustering of the nounces that seems to indicated similar miner or hardware. Ask him. Since the first block ins mined by AntPool and the others are anonymous, I assume that they use the same hardware. Otherwise we need to ask AntPool why they are anonymizing the next blocks if they are the miners.

It is also well known that a miner that mines a block has a higher probability of mining the next one since he can start mining in the time his block is propagating. Also there is a well known advantage in concealing mined blocks and releasing them altogether. This could indicate same miner.

Take a look at the timestamps now....
Hora de Recepción    2015-05-02 13:11:28
Hora de Recepción    2015-05-02 13:12:17
Hora de Recepción    2015-05-02 13:02:15
Hora de Recepción    2015-05-02 12:24:26

Did you even bother to verify with a second blockchain explorer?

https://btc.blockr.io/block/info/354640      
    2015-05-02 06:24:26
https://btc.blockr.io/block/info/354641
    2015-05-02 07:02:15
https://btc.blockr.io/block/info/354642
2015-05-02 07:12:17
https://btc.blockr.io/block/info/354643
2015-05-02 07:11:28

NO, the last 3 blocks were not mined within 1 min.

Perhaps the problem is you make wild assumptions without carefully studying the evidence?

"seems to indicate" is the same as "suggests the possibility" in my poor english.

Are you referring to your message to me 45 minutes ago?  You provided no information that wasn't in the thread; and I responded asking you to provide information (either privately or publicly, though I encouraged you to provide it in public.).

I and multiple others have explained to you multiple times now that various mining devices consider only subsets of nonces for completely boring reasons--; what isn't explained is why you keep alleging that something with a boring explanation which has been provided multiple times hasn't been explained.

A few week ago you were making posts that demonstrated that you had no idea how mining worked at all and were not willing or able to do even the most basic research on the subject.  Your posts here continue to show a remarkable lack of basic research, yet you expect people to believe that you know something that hasn't been discussed in the hundreds of past threads about low level mining optimizations by experts in the field (including people like the inventor of hashcash; the general scheme used). Moreover, you started this by deceptively asking a question you later claimed to "know the answer to"; so I hope you can understand why people are skeptical here.

You're making serious claims that would be concerns for the security of Bitcoin if true; such claims demand serious substantiation... doubly so when they coming form a source which seems to have been clearly deceptive in this very thread and is obviously not very familiar with the subject.

In any case, you need do nothing more to defend your reputation than to simply explain what you're thinking.  If your ideas are wrong, they'll be corrected; if they're right but not news, old threads will be referenced, if they're new and concerning the issues will be addressed if possible, etc.   Right now, though, you're basically trying to convince us of something for which you'll give none of the information which could be used to support your claim. The only content in this thread will be people attacking your methods and motivations as a result, since you are intentionally refusing to provide the only information which could be used to analyze your claim directly.

Dear gmaxwell,

You are right, I have no idea of what specific algorithms are using ASICs and that is what I was asking in that previous posts. I don't work on hardware. I guess you had to search through my post in lack of other arguments. This doesn't mean that I can't have some idea of how bitcoin mining works and what classical improvements can be made due to the particular structure of the block headers. You are making up that I am making claims about the security of bitcoin. That's untrue. First of all in order to raise concerns about bitcoin security, you will agree that you would need to boost the performance of the mining algorithm by several orders of magnitude. I never made such a claim.

On the other hand it would be worrysome if a number of people had access to a better mining algorithm that is used extensively and kept secret, and only for that reason it is worth analyzing unusual block validations.

I have no reputation to defend while I am being accused without grounds of being a scamer. My reputation is well, thank you for your concern.

I withdraw any claim that I may have made. So I am not trying to convince you about anything. I stand my claim that I see some unusual statistics on these blocks. Of course this doesn't prove anything and your explanations are most probably correct, so you can continue to sleep well. Be in peace. If you happen to find better explanations I, and others, would be glad to hear about them.

I already retracted everything, so I wait you to remove your negative rating and scam accusations :

https://bitcointalk.org/index.php?action=trust;u=11425



Best regards.

We never heard back of jl2012.

I guess he agrees that my argument wasn't fallacious. I withdraw most claims, but I stand by the claim that to see 144 times heads in 144 coin throws is very unlikely.

I will run some statistics on nounces. I am now very curious about their distribution. Anyone did study that before? 

 

Is this kind of comment acceptable in the circles you normally travel in?  If one of the people I worked with presented an argument of this form my response would be "Shame on you".  Perhaps jl2012 has other things to do than click reload constantly and wade through the page and pages of untrimmed quotations in your message?

Doubly so when it has been very clearly explained that your statistical argument is outright incorrect already by others.  Miners do not select nonces uniformly for boring engineering reasons, this is a fact, it's the behavior of hardware sitting right next to me, it's easily observable on the blockchain.   Your statistical argument is that IF nonces were uniform then it would be unlikely to see a run of similar ones.  You do not correct for multiple comparisons (we've had some 354k possible runs of 4 for this to be true in), but most importantly you seem to strangely continue to ignore the fact that we know that various hardware does not uniformly select nonces; and instead you suggest this is evidence of your secret hypothesis. Why are you surprised that we reject your reasoning and instead question your motivations?

The nonces here aren't even that close-- 2167965896, 2148513297, 2143118375, 2456983311  spans 7% of the nonce range...  Since people seem to get caught up on the the analysis, perhaps a numerical example in python might simplify things for people:


import random

trys = 1000000
threshold = 2456983311 - 2143118375
small_rng = 0
for i in xrange(trys):
  n = [random.randrange(0,2**32) for ii in xrange(4)]
  small_rng += (max(n)-min(n))<=threshold
  
print("Out of %d tries, %d groups of 4 nonces were spanned a range equal or smaller than %d."%(trys,small_rng,threshold))
print("Since there are 144 blocks (thus 144 overlapping groups of 4)")
print("We'd expect to see this every %f days with _uniform_ nonces."%(1./(float(small_rng)/trys*144.)))


Which yields:

Out of 1000000 tries, 1524 groups of 4 nonces were spanned a range equal or smaller than 313864936.
Since there are 144 blocks (thus 144 overlapping groups of 4)
We'd expect to see this every 4.556722 days with _uniform_ nonces.


Since we also know existing hardware produces a subset of nonces we should probably expect these runs to be even more common than the above reflects.
To get a feel for how non-uniformity changes this, switching to an RNG with a linear sloping probability, abs(random.randrange(0,2**32)-random.randrange(0,2**32)), increases the rate of these 'small' spans by about 2.8x.

Without a reason to believe the exact criteria was established in advance instead of based on the data we should also probably be correcting for the fact that there are many other possible "patterns" people might find interesting and might use to claim support for some secret theory; e.g. ending with certain digits in some base, or being close mod 2^32, having digits that are cyclic shifts of each other in some base, being close by a larger but also 'small' threshold (E.g. the post originally claimed 6 blocks with a nonce span of 1856814243 which we'd expect to see a bit over 8 times per day.), or having some other simple arithmetic relation, etc.