<p>We have a unique merkle root for each block in Bitcoin. Next block's merkle root does not use the merkle root of the previous blocks as a proof. As a result we do not have old merkle tree hash and new merkle tree hash. Also, the way of pairwise hashing is different. If you look at Figure 2 in your link, the certificates d4 and d5 are at a higher level than d1-3. In Bitcoin, all the certificates would have been at the same level, resulting in hashing between i &amp; j and k &amp; k (yes, in case of odd number, we hash the same result with it self).</p>

<p>However, if you look in figure 5 of the link you attached, the way of providing proof that a certificate exists is the same way a proof is provide to a SPV node in Bitcoin.</p>

CC BY-SA 4.0
2019-08-01T11:11:20.817Z
Thanks. Just concerning: _"in case of odd number, we hash the same result with it self."_ But in Figure_2 you addressed, there are 6 certificates (d0 to d5), and it is not odd. I do not know why the tree has been formed like that, where the number of certificates are "even". Thank you.
Questioner
CC BY-SA 4.0
2019-08-01T11:32:15.880Z
Although it is not odd, if it started at the same level then at the k level you will have 3 hashes (i, j, k), and hence you will have to duplicate k. Starting at one level above they can avoid that step. For example if they wanted to append two more certificates to Figure 4, they will have just hash the red block (o) with hash of those two new ceritificates to get a new merkle hash. That allows easier appending.
Ugam Kamat
CC BY-SA 4.0
2019-08-01T11:01:13.347Z
2019-08-01T11:01:13.347Z
Ugam Kamat
<p>The following article explains the process of <strong>"Merkle Audit Proofs of Certification"</strong>. (<a href="http://www.certificate-transparency.org/log-proofs-work" rel="nofollow noreferrer">Link to the article</a>)</p>

<ul>
<li>Is the process the <strong>same</strong> as <strong>"Merkle Proofs in Bitcoin"</strong> ? </li>
<li><strong>If</strong> their process is <strong>not</strong> the same, <strong>what are differences</strong>?</li>
</ul>

CC BY-SA 4.0
2019-08-08T02:21:08.693Z
Please stop asking questions of the form "I see a random article mentioning a technical term I've seen elsewhere; are they related?". The only similarity is that they're both using Merkle trees. Commenting on how they differ is very hard; this would be obvious if you'd read the paper.
Pieter Wuille
<merkle-tree><merkleblock>
Merkle Audit Proofs of Certification vs. Bitcoin Merkle Proofs
Questioner
# Merkle Audit Proofs of Certification vs. Bitcoin Merkle Proofs

(Asked by: username_0 on 2019-08-01)

The following article explains the process of **"Merkle Audit Proofs of Certification"**. ([Link to the article](http://www.certificate-transparency.org/log-proofs-work))

* Is the process the **same** as **"Merkle Proofs in Bitcoin"** ?
* **If** their process is **not** the same, **what are differences**?

**Tags:** merkle-tree, merkleblock

> **Comments:**
> **username_1**: Please stop asking questions of the form "I see a random article mentioning a technical term I've seen elsewhere; are they related?". The only similarity is that they're both using Merkle trees. Commenting on how they differ is very hard; this would be obvious if you'd read the paper.  

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## 1 answers

### Answer by username_2 on 2019-08-01. Score: 1

We have a unique merkle root for each block in Bitcoin. Next block's merkle root does not use the merkle root of the previous blocks as a proof. As a result we do not have old merkle tree hash and new merkle tree hash. Also, the way of pairwise hashing is different. If you look at Figure 2 in your link, the certificates d4 and d5 are at a higher level than d1-3. In Bitcoin, all the certificates would have been at the same level, resulting in hashing between i & j and k & k (yes, in case of odd number, we hash the same result with it self).

However, if you look in figure 5 of the link you attached, the way of providing proof that a certificate exists is the same way a proof is provide to a SPV node in Bitcoin.

> **Comments:**
> **username_0**: Thanks. Just concerning: _"in case of odd number, we hash the same result with it self."_ But in Figure_2 you addressed, there are 6 certificates (d0 to d5), and it is not odd. I do not know why the tree has been formed like that, where the number of certificates are "even". Thank you.  
> **username_2**: Although it is not odd, if it started at the same level then at the k level you will have 3 hashes (i, j, k), and hence you will have to duplicate k. Starting at one level above they can avoid that step. For example if they wanted to append two more certificates to Figure 4, they will have just hash the red block (o) with hash of those two new ceritificates to get a new merkle hash. That allows easier appending.  

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