<blockquote>
<p>I'm trying to understand from the code whether knightmb's blockchain data would be verified on startup or not, but couldn't easily determine that.</p>
</blockquote>
<p>It would not be.</p>
<p><code>blkindex.dat</code> back then held the equivalent of what is now called the UTXO set (and more). If you'd copy a malicious one, it would be accepted without verification (as it is the outcome of verification itself).</p>

CC BY-SA 4.0
2022-05-12T16:07:19.867Z
Haha, that's fantastic. Those were different times... Thanks a lot!
Kalle Rosenbaum
CC BY-SA 4.0
2022-05-12T14:57:51.997Z
2022-05-12T14:57:51.997Z
Pieter Wuille
<p>As a response to <a href="https://en.bitcoin.it/wiki/Value_overflow_incident" rel="nofollow noreferrer">the overflow bug 2010</a>, Satoshi <a href="https://bitcointalk.org/index.php?topic=823.msg9548#msg9548" rel="nofollow noreferrer">wrote this post</a> asking people to download the blockchain (blk****.dat and blkindex.dat) from a specific user.</p>
<blockquote>
<p>Patch is uploaded to SVN rev 132!</p>
<p>For now, recommended steps:</p>
<ol>
<li>Shut down.</li>
<li>Download knightmb's blk
files.  (replace your blk0001.dat and blkindex.dat files)</li>
<li>Upgrade.</li>
<li>It should start out with less than 74000 blocks. Let it redownload
the rest.</li>
</ol>
<p>If you don't want to use knightmb's files, you could just delete your
blk*.dat files, but it's going to be a lot of load on the network if
everyone is downloading the whole block index at once.</p>
<p>I'll build releases shortly.</p>
</blockquote>
<p>I'm trying to understand from <a href="https://github.com/bitcoin/bitcoin/commit/d4c6b90ca3f9b47adb1b2724a0c3514f80635c84" rel="nofollow noreferrer">the code</a> whether knightmb's blockchain data would be verified on startup or not, but couldn't easily determine that.</p>
<p>Was the blockchain data that people downloaded verified by the code in subversion revision r132 (imported to git commit d4c6b90ca3f9b47adb1b2724a0c3514f80635c84)?</p>

<blockchain-fork><verification>
Was the "sideloaded" data verified by bitcoind during the value overflow bug?
Kalle Rosenbaum
# Was the "sideloaded" data verified by bitcoind during the value overflow bug?

(Asked by: username_0 on 2022-05-12)

As a response to [the overflow bug 2010](https://en.bitcoin.it/wiki/Value_overflow_incident), Satoshi [wrote this post](https://bitcointalk.org/index.php?topic=823.msg9548#msg9548) asking people to download the blockchain (blk\*\*\*\*.dat and blkindex.dat) from a specific user.

> Patch is uploaded to SVN rev 132!
>
> For now, recommended steps:
>
> 1. Shut down.
> 2. Download knightmb's blk
>    files. (replace your blk0001.dat and blkindex.dat files)
> 3. Upgrade.
> 4. It should start out with less than 74000 blocks. Let it redownload
>    the rest.
>
> If you don't want to use knightmb's files, you could just delete your
> blk\*.dat files, but it's going to be a lot of load on the network if
> everyone is downloading the whole block index at once.
>
> I'll build releases shortly.

I'm trying to understand from [the code](https://github.com/bitcoin/bitcoin/commit/d4c6b90ca3f9b47adb1b2724a0c3514f80635c84) whether knightmb's blockchain data would be verified on startup or not, but couldn't easily determine that.

Was the blockchain data that people downloaded verified by the code in subversion revision r132 (imported to git commit d4c6b90ca3f9b47adb1b2724a0c3514f80635c84)?

**Tags:** blockchain-fork, verification


---

## 1 answers

### Answer by username_1 on 2022-05-12. Score: 1 | Accepted answer

> I'm trying to understand from the code whether knightmb's blockchain data would be verified on startup or not, but couldn't easily determine that.

It would not be.

`blkindex.dat` back then held the equivalent of what is now called the UTXO set (and more). If you'd copy a malicious one, it would be accepted without verification (as it is the outcome of verification itself).

> **Comments:**
> **username_0**: Haha, that's fantastic. Those were different times... Thanks a lot!  

---

