<p>The SHA256 hash algorithm produces what looks exactly like a random number in the range 0 to 2<sup>256</sup>-1 (1.1579208923731619542357098500869e+77). Each of those values should be equally likely.</p>
<p>So if you produce a large number of these by altering the data to be hashed, <strong>you cannot <em>steer</em> the results and most of the results will be a large number</strong>.</p>
<p>Some of the results will be a small number and a few will be very small. It is perfectly possible that the first result that is small is also very small - there is nothing impossible or surprising about that.</p>
<p>Since the genesis block had no history, there should be no expectation that the target value was especially precisely calculated to match the exact hashing power available.</p>
<p>Furthermore, I would expect the target would have been high (low difficulty) since there were very few miners (only one?) - The higher the target, the more space there is for a solution to be some orders of magnitude smaller than necessary. If conversely the difficulty was so high that hashes had to be less than 42, there would be no room for a successful hash to be two orders of magnitude smaller than needed.</p>

CC BY-SA 4.0
2021-07-20T20:47:44.793Z
Why would a higher target mean lower difficulty? Sorry for noobish question.
anotherDev
CC BY-SA 4.0
2021-07-20T21:32:10.923Z
@anotherDev, suppose the miner's task is to throw a dart at a dartboard blindfolded and score less than some target number. The higher that target number is, the less difficult it is to get a lower score. See https://en.bitcoin.it/wiki/Target and https://en.bitcoin.it/wiki/Difficulty
RedGrittyBrick
CC BY-SA 4.0
2021-07-20T21:40:55.417Z
Related: https://bitcoin.stackexchange.com/a/102416/13866
RedGrittyBrick
CC BY-SA 4.0
2021-07-20T21:48:17.903Z
Ok. I will read them to know more. Thanks.
anotherDev
CC BY-SA 4.0
2021-07-18T15:39:42.483Z
2021-07-18T15:39:42.483Z
RedGrittyBrick
<p>Bitcoin difficulty is not determined by the &quot;number of zeros&quot;, but none the less the Bitcoin genesis block would satisfy a difficulty target substantially higher than might be expected. This doesn't really mean anything in the scheme of how the system operates, it's just a curiosity.</p>

CC BY-SA 4.0
2021-07-17T21:22:55.370Z
2021-07-19T14:06:37.950Z
2021-07-19T14:06:37.950Z
Claris
<p>The hash of the genesis block of bitcoin has two extra 0 as compared to other block hashes. According to the logic, it should have been the same as they all have the same difficulty. Why is it so? Was any special reason for doing so?</p>
<blockquote>
<p>Hash of genesis block :
000000000019d6689c085ae165831e934ff763ae46a2a6c172b3f1b60a8ce26f</p>
<p>Hash of block 1 :
00000000839a8e6886ab5951d76f411475428afc90947ee320161bbf18eb6048</p>
<p>Hash of block 2 :
000000006a625f06636b8bb6ac7b960a8d03705d1ace08b1a19da3fdcc99ddbd</p>
</blockquote>

<difficulty><genesis-block><block-header><block-hash>
Why does the Genesis block appear to have a lower hash than necessary?
Aman Gupta
# Why does the Genesis block appear to have a lower hash than necessary?

(Asked by: username_0 on 2021-07-17)

The hash of the genesis block of bitcoin has two extra 0 as compared to other block hashes. According to the logic, it should have been the same as they all have the same difficulty. Why is it so? Was any special reason for doing so?

> Hash of genesis block :
> 000000000019d6689c085ae165831e934ff763ae46a2a6c172b3f1b60a8ce26f
>
> Hash of block 1 :
> 00000000839a8e6886ab5951d76f411475428afc90947ee320161bbf18eb6048
>
> Hash of block 2 :
> 000000006a625f06636b8bb6ac7b960a8d03705d1ace08b1a19da3fdcc99ddbd

**Tags:** difficulty, genesis-block, block-header, block-hash


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## 2 answers

### Answer by username_1 on 2021-07-18. Score: 2

The SHA256 hash algorithm produces what looks exactly like a random number in the range 0 to 2256-1 (1.1579208923731619542357098500869e+77). Each of those values should be equally likely.

So if you produce a large number of these by altering the data to be hashed, **you cannot *steer* the results and most of the results will be a large number**.

Some of the results will be a small number and a few will be very small. It is perfectly possible that the first result that is small is also very small - there is nothing impossible or surprising about that.

Since the genesis block had no history, there should be no expectation that the target value was especially precisely calculated to match the exact hashing power available.

Furthermore, I would expect the target would have been high (low difficulty) since there were very few miners (only one?) - The higher the target, the more space there is for a solution to be some orders of magnitude smaller than necessary. If conversely the difficulty was so high that hashes had to be less than 42, there would be no room for a successful hash to be two orders of magnitude smaller than needed.

> **Comments:**
> **username_2**: Why would a higher target mean lower difficulty? Sorry for noobish question.  
> **username_1**: @username_2, suppose the miner's task is to throw a dart at a dartboard blindfolded and score less than some target number. The higher that target number is, the less difficult it is to get a lower score. See https://en.bitcoin.it/wiki/Target and https://en.bitcoin.it/wiki/Difficulty  
> **username_1**: Related: https://bitcoin.stackexchange.com/a/102416/13866  
> **username_2**: Ok. I will read them to know more. Thanks.  

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### Answer by username_3 on 2021-07-17. Score: 1

Bitcoin difficulty is not determined by the "number of zeros", but none the less the Bitcoin genesis block would satisfy a difficulty target substantially higher than might be expected. This doesn't really mean anything in the scheme of how the system operates, it's just a curiosity.


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