<blockquote>
  <p>The merkleroot being part of the block information is a validation shortcut?</p>
</blockquote>

<p>No. It is to commit all of the transactions included in the block. Otherwise the transactions would not be part of the block hash (which is really the hash of the block header).</p>

<blockquote>
  <p>Difficulty not being part of the block information is due to the fact this can be derrived from the version header? (but this would require to have all difficulties being hardcoded forever into the code? This doesn't rhyme with dynamic difficulty, so basically I am wondering how a block can be validated without seemingly "knowing" its difficulty)</p>
</blockquote>

<p>The difficulty is included in the block header as part of the nBits field. The nBits field is a compact representation of the target that the block hash must be less than.</p>

CC BY-SA 3.0
2017-10-02T15:06:25.360Z
2017-10-02T15:06:25.360Z
Ava Chow
<p>Actually it kinda is, the nBits field encodes the target threshold in the block header, which is directly related to, and more directly useful than, the difficulty itself.</p>

CC BY-SA 3.0
2017-10-02T10:13:17.167Z
2017-10-02T10:13:17.167Z
meshcollider
<p>After some consideration I came up with two assumptions, please correct me if I am way off here.</p>

<ul>
<li><p>The merkleroot being part of the block information is a validation shortcut?</p></li>
<li><p>Difficulty not being part of the block information is due to the fact this can be derrived from the version header? (but this would require to have all difficulties being hardcoded forever into the code? This doesn't rhyme with dynamic difficulty, so basically I am wondering how a block can be validated without seemingly "knowing" its difficulty)</p></li>
</ul>

<blockchain><block><block-validity>
In blockchain, particular bitcoin why is difficulty not part of the Block but merkleroothash is
JX. Unit
# In blockchain, particular bitcoin why is difficulty not part of the Block but merkleroothash is

(Asked by: username_0 on 2017-10-02)

After some consideration I came up with two assumptions, please correct me if I am way off here.

* The merkleroot being part of the block information is a validation shortcut?
* Difficulty not being part of the block information is due to the fact this can be derrived from the version header? (but this would require to have all difficulties being hardcoded forever into the code? This doesn't rhyme with dynamic difficulty, so basically I am wondering how a block can be validated without seemingly "knowing" its difficulty)

**Tags:** blockchain, block, block-validity


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## 2 answers

### Answer by username_1 on 2017-10-02. Score: 1 | Accepted answer

> The merkleroot being part of the block information is a validation shortcut?

No. It is to commit all of the transactions included in the block. Otherwise the transactions would not be part of the block hash (which is really the hash of the block header).

> Difficulty not being part of the block information is due to the fact this can be derrived from the version header? (but this would require to have all difficulties being hardcoded forever into the code? This doesn't rhyme with dynamic difficulty, so basically I am wondering how a block can be validated without seemingly "knowing" its difficulty)

The difficulty is included in the block header as part of the nBits field. The nBits field is a compact representation of the target that the block hash must be less than.


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### Answer by username_2 on 2017-10-02. Score: 1

Actually it kinda is, the nBits field encodes the target threshold in the block header, which is directly related to, and more directly useful than, the difficulty itself.


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