<p>You may be looking at transactions of an unknown entity dubbed &quot;Crazy1o1&quot;. To my knowledge, it is still unknown who they are or why they are using 1-of-1 transactions, but they've been active for years. Notable mentions:</p>
<ul>
<li>LaurentMT first <a href="https://twitter.com/LaurentMT/status/1264586463536189444" rel="nofollow noreferrer">describing and naming Crazy1o1</a></li>
<li>LaurentMT analyzing some <a href="https://twitter.com/LaurentMT/status/1264958123275681793" rel="nofollow noreferrer">traffic of Crazy1o1</a></li>
<li>Stepan Snigirev <a href="https://twitter.com/StepanSnigirev/status/1413156991606865924" rel="nofollow noreferrer">asking</a> about 1-of-1 transactions</li>
<li><a href="https://twitter.com/ziggamon/status/1264233427840176129" rel="nofollow noreferrer">Crazy1o1 consolidating</a> 720k+ UTXOs at over 100 s/vB while the mempool was essentially empty</li>
<li>On-going traffic of <a href="https://mempool.observer/monitor/?filter=WD0xLW9mLTE%3D" rel="nofollow noreferrer">1-of-1 multisig transactions</a></li>
<li><a href="https://oxt.me/entity/tiid/3498542669" rel="nofollow noreferrer">Crazy1o1</a> on OXT.me</li>
</ul>
<p>Update: LaurentMT suggests that Crazy1o1 is a <a href="https://twitter.com/LaurentMT/status/1577023660153413632" rel="nofollow noreferrer">“Crypto and Forex broker named KOT4X”</a></p>

CC BY-SA 4.0
2022-10-03T19:10:03.983Z
2022-10-03T19:57:26.810Z
2022-10-03T19:57:26.810Z
Murch
<p>Today I noticed a transaction that spends a bunch of 1-of-1 multisig P2WSH inputs:<br />
<a href="https://mempool.space/tx/675b106c71f110ebca9e6435f49508a07b45d40d38e237d02b89e5506f3b136b" rel="nofollow noreferrer">675b106c71f110ebca9e6435f49508a07b45d40d38e237d02b89e5506f3b136b</a></p>
<p>For example, the first input has this script in the witness:</p>
<pre><code>OP_PUSHNUM_1
OP_PUSHBYTES_33 031f1c516fc9362202883b24fd92e6548776a8f1701baca38b63bbe635da8a82f7
OP_PUSHNUM_1
OP_CHECKMULTISIG
</code></pre>
<p>I then wrote a script to find more of these transactions, and it turns out in the last 1000 blocks there were 3883 transactions spending 1-of-1 multisig inputs. This one spends over 30 BTC: <a href="https://mempool.space/tx/4d8a475e7a0433ef84baec9ec941342cb31d4194b42dedccdc4503e4acad02f8" rel="nofollow noreferrer">4d8a475e7a0433ef84baec9ec941342cb31d4194b42dedccdc4503e4acad02f8</a></p>
<p>Why would anyone use this instead of P2WPKH which is both cheaper and has a larger anonymity set?</p>

<multi-signature>
Why would someone use 1-of-1 multisig?
Vojtěch Strnad
# Why would someone use 1-of-1 multisig?

(Asked by: username_0 on 2022-10-03)

Today I noticed a transaction that spends a bunch of 1-of-1 multisig P2WSH inputs:
675b106c71f110ebca9e6435f49508a07b45d40d38e237d02b89e5506f3b136b
For example, the first input has this script in the witness:
OP_PUSHNUM_1
OP_PUSHBYTES_33 031f1c516fc9362202883b24fd92e6548776a8f1701baca38b63bbe635da8a82f7
OP_PUSHNUM_1
OP_CHECKMULTISIG

I then wrote a script to find more of these transactions, and it turns out in the last 1000 blocks there were 3883 transactions spending 1-of-1 multisig inputs. This one spends over 30 BTC: 4d8a475e7a0433ef84baec9ec941342cb31d4194b42dedccdc4503e4acad02f8
Why would anyone use this instead of P2WPKH which is both cheaper and has a larger anonymity set?

**Tags:** multi-signature


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## 1 answers

### Answer by username_1 on 2022-10-03. Score: 8 | Accepted answer

You may be looking at transactions of an unknown entity dubbed "Crazy1o1". To my knowledge, it is still unknown who they are or why they are using 1-of-1 transactions, but they've been active for years. Notable mentions:

* LaurentMT first [describing and naming Crazy1o1](https://twitter.com/LaurentMT/status/1264586463536189444)
* LaurentMT analyzing some [traffic of Crazy1o1](https://twitter.com/LaurentMT/status/1264958123275681793)
* Stepan Snigirev [asking](https://twitter.com/StepanSnigirev/status/1413156991606865924) about 1-of-1 transactions
* [Crazy1o1 consolidating](https://twitter.com/ziggamon/status/1264233427840176129) 720k+ UTXOs at over 100 s/vB while the mempool was essentially empty
* On-going traffic of [1-of-1 multisig transactions](https://mempool.observer/monitor/?filter=WD0xLW9mLTE%3D)
* [Crazy1o1](https://oxt.me/entity/tiid/3498542669) on OXT.me

Update: LaurentMT suggests that Crazy1o1 is a [“Crypto and Forex broker named KOT4X”](https://twitter.com/LaurentMT/status/1577023660153413632)


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