<p>See <a href="https://bitcoin.stackexchange.com/questions/2177/how-to-calculate-a-hash-of-a-tx">How to calculate a hash of a Tx?</a> .  The hash that serves as the ID of the transaction is not the same hash that is used for signing.</p>

CC BY-SA 3.0
2013-11-17T08:32:21.630Z
That's the answer to a different question. If you follow the link given in that answer (to a post of Andresen in the bitcointalk forum) and scroll to the post by etotheipi, a couple of posts below, you will see that.
Felipe Voloch
CC BY-SA 3.0
2013-11-17T05:32:45.607Z
2013-11-17T05:32:45.607Z
2017-04-13T12:47:36.707Z
RentFree
<p>I know there are many tools to check an ecdsa signature of a bitcoin transaction and I understand the ecdsa algorithm. It takes three inputs, a hash of the transaction, the digital signature and the public key of the sender. </p>

<p>In a raw transaction such as this one: 
<a href="http://blockexplorer.com/rawtx/9b4912711de5e258a74a529227f43647bc3b2304212fb508c5f8e910d5986270">http://blockexplorer.com/rawtx/9b4912711de5e258a74a529227f43647bc3b2304212fb508c5f8e910d5986270</a></p>

<p>I know the signature is the first line of the Scriptsig and the public key is the second and I assumed that the hash of the transaction is the first line on the page (also in the URL) but they don't validade and I've tried a handful of transactions from blockexplorer. </p>

<p>My question is, what do I take as the first variable to validate a transaction in that form? </p>

CC BY-SA 3.0
2015-08-12T03:50:35.340Z
possible duplicate http://bitcoin.stackexchange.com/q/32305/12983
amaclin
<signature><blockexplorer>
How to verify the signature of a raw transaction
Felipe Voloch
# How to verify the signature of a raw transaction

(Asked by: username_0 on 2013-11-17)

I know there are many tools to check an ecdsa signature of a bitcoin transaction and I understand the ecdsa algorithm. It takes three inputs, a hash of the transaction, the digital signature and the public key of the sender.

In a raw transaction such as this one:
<http://blockexplorer.com/rawtx/9b4912711de5e258a74a529227f43647bc3b2304212fb508c5f8e910d5986270>

I know the signature is the first line of the Scriptsig and the public key is the second and I assumed that the hash of the transaction is the first line on the page (also in the URL) but they don't validade and I've tried a handful of transactions from blockexplorer.

My question is, what do I take as the first variable to validate a transaction in that form?

**Tags:** signature, blockexplorer

> **Comments:**
> **username_1**: possible duplicate http://bitcoin.stackexchange.com/q/32305/12983  

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## 1 answers

### Answer by username_2 on 2013-11-17. Score: 2

See [How to calculate a hash of a Tx?](https://bitcoin.stackexchange.com/questions/2177/how-to-calculate-a-hash-of-a-tx) . The hash that serves as the ID of the transaction is not the same hash that is used for signing.

> **Comments:**
> **username_0**: That's the answer to a different question. If you follow the link given in that answer (to a post of Andresen in the bitcointalk forum) and scroll to the post by etotheipi, a couple of posts below, you will see that.  

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