why do people keep commenting on imperis posts? arent you the same guy proposed that bitcoin will have a negative value in usd?
just void the post.
Topic: SHA-256 (fixed: maybe) hacked, man gets away with 7 blocks in 10 minutes (Read 9382 times)
June 22, 2011, 12:13:44 PM
June 22, 2011, 10:24:14 AM
I ran some quick numbers. If I'm correctly understanding the distribution, once the first block was found, the chance of finding the next 6 blocks in that time window was something like 0.0000002. However, this possibility has existed every time a block has been found. The chance of this streak happening at least once in 132000 or so blocks is greater than 99.7%. In fact, there is a very high chance that his has happened more than once. If I find the time, I could do an analysis of the whole block chain to see if this has happened before.
Is there an easy way to extract block timestamps from the chain?
If you evaluated the cdf of a gamma distribution with parameters 7 and 1/10min at 10min to get 0.0000002, and 1 - the pdf of the binomial distribution with parameters 132000 and 0.0000002 evaluated at 0 to get 99.7%, then I think it's correct. I'm too lazy to calculate it, though.Is there an easy way to extract block timestamps from the chain?
Also, http://www.xkcd.com/882/
My knowledge of statistics is a bit rusty, so I decided to look at the actual blocks. I ran a script to evaluate, from each block, how many blocks were found less than 420 seconds beforehand.
The record was twelve.
There were 358 cases of 6 or more (ie. 7 blocks in under 7 minutes). If we only look at recent blocks (>100000), we still get nine cases of this happening.
June 22, 2011, 09:59:45 AM
June 22, 2011, 08:00:56 AM
Well that's it for me. Selling every coin I own. I advise others do the same.
I'll buy them at a dollar a piece.
June 22, 2011, 07:58:36 AM
Didn't japan just launch a computer that can do a quadrillion flops/sec?
No they didn't. They launched a computed with the power of about 7% of the entire bitcoin network. No need to worry.
June 22, 2011, 07:27:16 AM
I ran some quick numbers. If I'm correctly understanding the distribution, once the first block was found, the chance of finding the next 6 blocks in that time window was something like 0.0000002. However, this possibility has existed every time a block has been found. The chance of this streak happening at least once in 132000 or so blocks is greater than 99.7%. In fact, there is a very high chance that his has happened more than once. If I find the time, I could do an analysis of the whole block chain to see if this has happened before.
Is there an easy way to extract block timestamps from the chain?
If you evaluated the cdf of a gamma distribution with parameters 7 and 1/10min at 10min to get 0.0000002, and 1 - the pdf of the binomial distribution with parameters 132000 and 0.0000002 evaluated at 0 to get 99.7%, then I think it's correct. I'm too lazy to calculate it, though.Is there an easy way to extract block timestamps from the chain?
Also, http://www.xkcd.com/882/
June 22, 2011, 06:53:41 AM
BTCGuild found 5 blocks in 10 minutes or so. No random SHA256 crack unless they were stupid enough to share the wealth and ingenious enough to crack it... lol @ conspiracy theorists
June 22, 2011, 06:27:01 AM
No.
I ran some quick numbers. If I'm correctly understanding the distribution, once the first block was found, the chance of finding the next 6 blocks in that time window was something like 0.0000002. However, this possibility has existed every time a block has been found. The chance of this streak happening at least once in 132000 or so blocks is greater than 99.7%. In fact, there is a very high chance that his has happened more than once. If I find the time, I could do an analysis of the whole block chain to see if this has happened before.
Is there an easy way to extract block timestamps from the chain?
June 22, 2011, 01:30:11 AM
Didn't japan just launch a computer that can do a quadrillion flops/sec?
That'll only work 1/5th of the time then anyway, due to the rolling power outages they still have
June 22, 2011, 12:35:35 AM
Yes, the promise of bitcoins, which in TOTAL, at their PEAK was worth less than 40 million dollars (Current Block # * Peak Price) is far more alluring than all of the bank systems relying on SHA256 encryption, all the SSH tunnels to be sniffed, government secrets, crime syndication, encrypted emails, and all the fame of being the one who broke it.
You're off by a factor of 50.
current block# * peak price * 50 coins per block.
There's over 6.6 million coins out there right now. Even at $15 that's $99 million. At the peak it was ~ 6 million * $30. 180 million.
Right, forgot that, still, paltry compared to the lure of all the above.
June 22, 2011, 12:04:30 AM
yeah it's interesting, I wonder if it's possible to try and log the ip addresses of all block solvers? I would guess it's not in the client though since it violates privacy.
so no there is not way to detect it as long as the attacker uses separate addresses for each block.
so no there is not way to detect it as long as the attacker uses separate addresses for each block.
June 22, 2011, 12:04:03 AM
Yes, the promise of bitcoins, which in TOTAL, at their PEAK was worth less than 40 million dollars (Current Block # * Peak Price) is far more alluring than all of the bank systems relying on SHA256 encryption, all the SSH tunnels to be sniffed, government secrets, crime syndication, encrypted emails, and all the fame of being the one who broke it.
You're off by a factor of 50.
current block# * peak price * 50 coins per block.
There's over 6.6 million coins out there right now. Even at $15 that's $99 million. At the peak it was ~ 6 million * $30. 180 million.
June 21, 2011, 11:57:36 PM
Forgive my ignorance, but how do you tell that one person got all those blocks? Couldn't it have been multiple miners, and what are the statistics of that happening?
June 21, 2011, 11:31:04 PM
Finding a collision isn't breaking SHA256. Breaking SHA256 (or at least, any manner of breaking that would matter to us) is finding a FAST and EFFICIENT way to find a collision, other than brute forcing. There is no way to do this that is currently known, and it's stood up to many many cryptographic tests and analysis, people trying to hack it for years.
well its different when you just work for your guaranteed wages and when there is a instant free big money floating, people could improve in their skills considerably with the right motivation.
However this is most probably a supercomputer working for a short time. Or more probably a good luck.
Yes, the promise of bitcoins, which in TOTAL, at their PEAK was worth less than 40 million dollars (Current Block # * Peak Price) is far more alluring than all of the bank systems relying on SHA256 encryption, all the SSH tunnels to be sniffed, government secrets, crime syndication, encrypted emails, and all the fame of being the one who broke it.
Also, nothing says this is the same person. If it went to multiple addresses, it could very well be multiple people. If it went to the same address, that could be one of the larger pools' addresses. The conspiracy theorists in this forum are growing thick as mud.
ok since clearly you like conspiracy theories so much i will give you another one, my today's special! i invented this one just now while walking to work.
imagine how much people want to crack sha256.
before bitcoin: a bunch of professional security specialists. also criminals but they lack the skillz anyway.
after bitcoin: basically every single geek on this planet who is capable of reading a C source code of SHA256 implementation. they are not criminals mostly, or if some of them potentially are, they have other means to live and criminal activities are not their strongest suit anyway.
which is orders of magnitude more.
so here is the conspiracy theory: satoshi is basically a security expert of sorts who is testing his new method of brute forcing the security algorithms. basically all the geeks on this planet are raw computational power that tries to solve the SHA256 hash with their feeble minds. just like with mining, one by one they have very little chances to solve it, but working at once on the same task they might solve the block much faster!
we'll see how it goes
June 21, 2011, 10:49:06 PM
June 21, 2011, 10:47:05 PM
Finding a collision isn't breaking SHA256. Breaking SHA256 (or at least, any manner of breaking that would matter to us) is finding a FAST and EFFICIENT way to find a collision, other than brute forcing. There is no way to do this that is currently known, and it's stood up to many many cryptographic tests and analysis, people trying to hack it for years.
well its different when you just work for your guaranteed wages and when there is a instant free big money floating, people could improve in their skills considerably with the right motivation.
However this is most probably a supercomputer working for a short time. Or more probably a good luck.
Yes, the promise of bitcoins, which in TOTAL, at their PEAK was worth less than 40 million dollars (Current Block # * Peak Price) is far more alluring than all of the bank systems relying on SHA256 encryption, all the SSH tunnels to be sniffed, government secrets, crime syndication, encrypted emails, and all the fame of being the one who broke it.
Also, nothing says this is the same person. If it went to multiple addresses, it could very well be multiple people. If it went to the same address, that could be one of the larger pools' addresses. The conspiracy theorists in this forum are growing thick as mud.
Multiplication fail.
Also D- in foresight.
June 21, 2011, 10:36:43 PM
Finding a collision isn't breaking SHA256. Breaking SHA256 (or at least, any manner of breaking that would matter to us) is finding a FAST and EFFICIENT way to find a collision, other than brute forcing. There is no way to do this that is currently known, and it's stood up to many many cryptographic tests and analysis, people trying to hack it for years.
well its different when you just work for your guaranteed wages and when there is a instant free big money floating, people could improve in their skills considerably with the right motivation.
However this is most probably a supercomputer working for a short time. Or more probably a good luck.
Yes, the promise of bitcoins, which in TOTAL, at their PEAK was worth less than 40 million dollars (Current Block # * Peak Price) is far more alluring than all of the bank systems relying on SHA256 encryption, all the SSH tunnels to be sniffed, government secrets, crime syndication, encrypted emails, and all the fame of being the one who broke it.
Also, nothing says this is the same person. If it went to multiple addresses, it could very well be multiple people. If it went to the same address, that could be one of the larger pools' addresses. The conspiracy theorists in this forum are growing thick as mud.
June 21, 2011, 10:33:14 PM
This thread is completely worthless until someone posts the mathematical odds of this happening (relative to how long bitcoin mining has been taking place and/or current difficulty rates and hashing power).
June 21, 2011, 10:30:55 PM
Why is it every morons wet dream for this currency to fail? Is it because you can't afford mining equipment? Is it because you can't afford to buy any coins? Is it that your TO LAZY AND WON'T WORK FOR THE CURRENCY SO YOU MIGHT AS WELL TRY TO DESTROY IT?
June 21, 2011, 10:18:18 PM
Man, that would be such a waste. If I had special hashing powers, I'd make hash browns all over the place. I'd make a bed out of them and then I could wake up in the middle of the night and snack without even leaving my nice warm bed. Oh man that's always been my dream.
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