<p>For Bitcoin, you can use block explorers like Blockchain.info, Blockchair, or a blockchain API like Blockcypher. They often provide detailed information about transactions, including inputs and outputs.</p>
<p>Here's a high-level approach:</p>
<ol>
<li><p>Identify Multisig Transaction: Find the transaction where the multisig script was used.</p>
</li>
<li><p>Explore Transaction Outputs: Look at the outputs of that transaction. Multisig transactions usually involve several public keys.</p>
</li>
<li><p>Search for Public Keys: Take each public key and search for them in other transactions. You may need to decode these public keys to their standard format for searching.</p>
</li>
<li><p>Consider Output Types: As you mentioned, understanding different output types is crucial. For multisig, you'd be dealing with P2SH (Pay-to-Script-Hash) or even more complex script types.</p>
</li>
<li><p>Decode Scripts: Some explorers allow you to decode scripts, helping you understand the script type and extract public keys.</p>
</li>
</ol>
<p>This process might require some programming/scripting if you're dealing with a large number of transactions or public keys. Python with libraries like <code>bitcoinlib</code> or <code>pybitcointools</code> could be helpful.</p>

CC BY-SA 4.0
2023-10-12T08:23:14.193Z
2023-10-12T08:23:14.193Z
Mani T
<p>When we get the public keys from a multisig script is there a way to check what other transactions use those public keys?</p>
<p>I know how to check if they have been used as P2PKH addresses, but I'm not sure how to check other output types.</p>

CC BY-SA 4.0
2023-10-12T01:40:13.387Z
Hi user2334659, I've edited the question to hopefully make it clearer. If I've somehow changed the intent of your original question, feel free to change it back.
Vojtěch Strnad
<multi-signature><public-key>
How to find out if public keys have been used in other transactions
user2334659
# How to find out if public keys have been used in other transactions

(Asked by: username_0 on 2023-10-07)

When we get the public keys from a multisig script is there a way to check what other transactions use those public keys?

I know how to check if they have been used as P2PKH addresses, but I'm not sure how to check other output types.

**Tags:** multi-signature, public-key

> **Comments:**
> **username_1**: Hi username_0, I've edited the question to hopefully make it clearer. If I've somehow changed the intent of your original question, feel free to change it back.  

---

## 1 answers

### Answer by username_2 on 2023-10-12. Score: 1

For Bitcoin, you can use block explorers like Blockchain.info, Blockchair, or a blockchain API like Blockcypher. They often provide detailed information about transactions, including inputs and outputs.

Here's a high-level approach:

1. Identify Multisig Transaction: Find the transaction where the multisig script was used.
2. Explore Transaction Outputs: Look at the outputs of that transaction. Multisig transactions usually involve several public keys.
3. Search for Public Keys: Take each public key and search for them in other transactions. You may need to decode these public keys to their standard format for searching.
4. Consider Output Types: As you mentioned, understanding different output types is crucial. For multisig, you'd be dealing with P2SH (Pay-to-Script-Hash) or even more complex script types.
5. Decode Scripts: Some explorers allow you to decode scripts, helping you understand the script type and extract public keys.

This process might require some programming/scripting if you're dealing with a large number of transactions or public keys. Python with libraries like `bitcoinlib` or `pybitcointools` could be helpful.


---

