<p>There is no way to check the transaction separately for each signature. Either the entire transaction is valid or it is invalid. When you receive the partially signed transaction, you would need to sign it with your own private key using the <code>signrawtransaction</code> command in bitcoind. It would give you two outputs (1) <code>hex</code> which is the serialized transaction and (2) <code>complete</code>. If the second output shows you <code>"complete": true</code>, then the transaction you received was signed with a valid private key. If it shows <code>false</code> then it wasn't.</p>

CC BY-SA 4.0
2019-07-28T05:24:19.127Z
Technically, there is. In fact that is exactly what happens under the hood, each signature is verified individually and when all signatures verify, the whole transaction becomes valid. So when you receive a partially signed transaction, you could take the same steps to first verify whether the provided signature is correct or not then sign it with your own key.
Coding Enthusiast
CC BY-SA 4.0
2019-04-26T14:29:51.943Z
2019-04-26T15:58:36.333Z
2019-04-26T15:58:36.333Z
Ugam Kamat
<p>How to verify signature of multisig transaction (2-2) after it being signed by first owner? How can I understand if that owner used wrong private key => wrong signature?</p>

<bitcoin-core><multi-signature><cryptography><ecdsa><p2sh>
How to verify signature of multisig transaction
newbie
# How to verify signature of multisig transaction

(Asked by: username_0 on 2019-04-26)

How to verify signature of multisig transaction (2-2) after it being signed by first owner? How can I understand if that owner used wrong private key => wrong signature?

**Tags:** bitcoin-core, multi-signature, cryptography, ecdsa, p2sh


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## 1 answers

### Answer by username_1 on 2019-04-26. Score: 1 | Accepted answer

There is no way to check the transaction separately for each signature. Either the entire transaction is valid or it is invalid. When you receive the partially signed transaction, you would need to sign it with your own private key using the `signrawtransaction` command in bitcoind. It would give you two outputs (1) `hex` which is the serialized transaction and (2) `complete`. If the second output shows you `"complete": true`, then the transaction you received was signed with a valid private key. If it shows `false` then it wasn't.

> **Comments:**
> **username_2**: Technically, there is. In fact that is exactly what happens under the hood, each signature is verified individually and when all signatures verify, the whole transaction becomes valid. So when you receive a partially signed transaction, you could take the same steps to first verify whether the provided signature is correct or not then sign it with your own key.  

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