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# Tag Info

Accepted

### What is the relationship between parity and the sign of the points on the elliptic curve?

First some background The X and Y coordinates of an elliptic curve are not integers. They are elements of a finite field. In secp256k1, that is the modulo p = 2256-232-977 field. In your example, that ...
• 108k
Accepted

### Is it possible to calculate the correct y coordinate from x coordinate given only x coordinate without any prefix

There is no known relation between the parity of the Y coordinate and any property of the private key (like whether it's in the low or high half). In BIP340, which defines the Schnorr-based digital ...
• 108k

### Is it possible to reduce the field size without disrupting generation of public keys?

i was wondering if its possible to reduce to field to a 130 bit or lower No, that would be woefully insecure. The security of elliptic curve cryptography scales with the half of the field size. A 133-...
• 108k

### Low vs High R value signatures

In DER-encoded signatures, the r and s values need to be prepended with 0x00 only if they start with the byte 0x80 or higher (i.e. have their first bit set). The r-value of the first signature starts ...
• 9,004
1 vote
Accepted

### Why do we have "circular behavior" when working with EC over finite field and what makes some point a "turning point"?

The points on an elliptic curve, combined with the point at infinity, and the point addition operation, define a group. I consider explaining why that is outside of the scope of this site, but it ...
• 108k
1 vote
Accepted

### What am I doing wrong in calculating point addition? Is something redundant in the formula I am using?

My point was that regardless of whether you do a modulo operation or not, you'll end up with the same point - if you treat differences of a multiple of 11 as "identical". If of course you do ...
• 108k

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