<p>No, the SHA2 hashing function is not vulnerable to any known attack that significantly reduces the difficulty of finding a block, but it is a highly random process.</p>

<p>Randomness is funny sometimes. Statistically it it works out to be even over a longer time period or larger population, but if you focus in on a small set of samples sometimes you see a cluster or a gap. This is why the estimated hash rate of the network on blockchain.info is woefully inaccurate on anything less than a multi-day average, and bitcoin is based on a 2 week correction period instead of a smaller number.</p>

<p>(which is why the unlucky miner can't expect to find 2 blocks quickly "because" he had a drought, and you should not expect a gap to "make up for" earlier luck, it's the  population that matters.)</p>

CC BY-SA 3.0
2013-12-03T06:01:49.690Z
I think this answer is correct, but I'd like to add a comment regarding potential foul play with quick consecutive blocks by the same miner/pool. The vulnerability, already widely discussed, is where a block found by the miner is kept private and not broadcast immediately, giving the miner/pool a slight head start on the next block, at the potential risk of having the original block go orphaned.
ktorn
CC BY-SA 3.0
2013-12-03T06:24:56.273Z
I agree, that the luck will even out in the end, but that doesn't show that you couldn't find a block every hash right? You have the same chance each block, isn't there then a chance that you could find n blocks in a row? Though the chance is probably amazingly incomprehensibly low.
KDecker
CC BY-SA 3.0
2013-12-03T05:51:30.377Z
2013-12-03T05:51:30.377Z
Scrybe
<p>I understand the output of the SHA-256 hashing function is a random number between 0 and 2^256. Does the randomness of this output imply that there cannot be a, so to say, honey hole in the hashing. </p>

<p>For instance this reddit post, <a href="http://www.reddit.com/r/BitcoinMining/comments/1rysqh/is_there_something_strange_about_block_272754_and/" rel="nofollow">http://www.reddit.com/r/BitcoinMining/comments/1rysqh/is_there_something_strange_about_block_272754_and/</a></p>

<p>They point out that someone relayed two blocks very close together, approximately 10s apart. Could they have found an occurrence where two block solving hashes sit close to each other?</p>

<p>I guess this kind of doesn't make sense though. Once a block is found, or a transaction is accepted, and even for each 3 seconds(timestamp) the block header is changed. So you would really could never find a block with the same hash just one number off (same block header, with two blocks one with nonce and the other nonce+1), because the first block will not be included in the second one, the second will become a dead fork in the blockchain?</p>

<hash><difficulty>
Is the idea of a "honey hole" such as in gold mining, present in bitcoin mining?
KDecker
# Is the idea of a "honey hole" such as in gold mining, present in bitcoin mining?

(Asked by: username_0 on 2013-12-03)

I understand the output of the SHA-256 hashing function is a random number between 0 and 2^256. Does the randomness of this output imply that there cannot be a, so to say, honey hole in the hashing.

For instance this reddit post, <http://www.reddit.com/r/BitcoinMining/comments/1rysqh/is_there_something_strange_about_block_272754_and/>

They point out that someone relayed two blocks very close together, approximately 10s apart. Could they have found an occurrence where two block solving hashes sit close to each other?

I guess this kind of doesn't make sense though. Once a block is found, or a transaction is accepted, and even for each 3 seconds(timestamp) the block header is changed. So you would really could never find a block with the same hash just one number off (same block header, with two blocks one with nonce and the other nonce+1), because the first block will not be included in the second one, the second will become a dead fork in the blockchain?

**Tags:** hash, difficulty


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## 1 answers

### Answer by username_1 on 2013-12-03. Score: 7 | Accepted answer

No, the SHA2 hashing function is not vulnerable to any known attack that significantly reduces the difficulty of finding a block, but it is a highly random process.

Randomness is funny sometimes. Statistically it it works out to be even over a longer time period or larger population, but if you focus in on a small set of samples sometimes you see a cluster or a gap. This is why the estimated hash rate of the network on blockchain.info is woefully inaccurate on anything less than a multi-day average, and bitcoin is based on a 2 week correction period instead of a smaller number.

(which is why the unlucky miner can't expect to find 2 blocks quickly "because" he had a drought, and you should not expect a gap to "make up for" earlier luck, it's the population that matters.)

> **Comments:**
> **username_2**: I think this answer is correct, but I'd like to add a comment regarding potential foul play with quick consecutive blocks by the same miner/pool. The vulnerability, already widely discussed, is where a block found by the miner is kept private and not broadcast immediately, giving the miner/pool a slight head start on the next block, at the potential risk of having the original block go orphaned.  
> **username_0**: I agree, that the luck will even out in the end, but that doesn't show that you couldn't find a block every hash right? You have the same chance each block, isn't there then a chance that you could find n blocks in a row? Though the chance is probably amazingly incomprehensibly low.  

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