<p>The result of an SHA256  operation is a typically presented as a 32-byte array or slice or similar structure. 32 x 8 = 256. It can be presented in software as an unsigned integer. It would arguably be wrong to interpret it as a signed integer. It is usually displayed in any convenient encoding such as Hex.</p>
<p>Either way there is only one &quot;solution&quot; - there is not an alternative negative solution. It is not like a U-shaped curve such as y=x^2 providing two solutions for x, positive and negative, for any positive value of y. It is just not that sort of thing. Producing a single unambiguous result is a desirable feature of a hashing algorithm.</p>

CC BY-SA 4.0
2022-11-06T11:07:21.473Z
2022-11-06T11:07:21.473Z
RedGrittyBrick
<p>Is there such a value as a negative Z or inverse Z related to the original Z value, which is the double SHA256 of the unsigned tx+01000000. I know there is a negative S value, is there a negative Z as well?</p>

CC BY-SA 4.0
2022-11-08T21:43:58.907Z
Does this answer your question? [How to get the Z value aka Hash of the outputs to be signed](https://bitcoin.stackexchange.com/questions/25387/how-to-get-the-z-value-aka-hash-of-the-outputs-to-be-signed)
Saxtheowl
<transactions><signature><sighash>
Question regarding the Z value of bitcoin Transaction
Gwer
# Question regarding the Z value of bitcoin Transaction

(Asked by: username_0 on 2022-11-06)

Is there such a value as a negative Z or inverse Z related to the original Z value, which is the double SHA256 of the unsigned tx+01000000. I know there is a negative S value, is there a negative Z as well?

**Tags:** transactions, signature, sighash

> **Comments:**
> **username_1**: Does this answer your question? [How to get the Z value aka Hash of the outputs to be signed](https://bitcoin.stackexchange.com/questions/25387/how-to-get-the-z-value-aka-hash-of-the-outputs-to-be-signed)  

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## 1 answers

### Answer by username_2 on 2022-11-06. Score: 2

The result of an SHA256 operation is a typically presented as a 32-byte array or slice or similar structure. 32 x 8 = 256. It can be presented in software as an unsigned integer. It would arguably be wrong to interpret it as a signed integer. It is usually displayed in any convenient encoding such as Hex.

Either way there is only one "solution" - there is not an alternative negative solution. It is not like a U-shaped curve such as y=x^2 providing two solutions for x, positive and negative, for any positive value of y. It is just not that sort of thing. Producing a single unambiguous result is a desirable feature of a hashing algorithm.


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