user128924: 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?

user13866: 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.

128924: <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>
 13866: <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>
