Quote from: Tanagi on Today at 03:35:00 AM

Thanks so much for everyone's input so far.

Could I ask if someone would be able to provide a manual step by step example of the point addition process using actual numbers?

Here are 2 random EC points to use from secp256k1.

Privkey: DBD5EBF749EDF69369B251A9434E9B782534294066797AEF1D25ED9B9672E821

x - 109493922098989287353358202596299422915042473617120228714701225409342421241792
y - 109899546570013792669570062242083808994383794323190482590108937934309418520644

+

Privkey: 9A309407E5266673F677C583BF1068615810AF4C1B90D5A8DBB335CC15D05959

x - 69395938208587572292363152174054021882846778300880058382874375807278603471216
y - 88660534177150263324537226657815045924854945333470172921739521551593497336256

I just need the (public key) point addition. No need to do anything with the private keys, they are just there for reference if needed.

I haven't seen this done anywhere (and I've looked a lot). This would be amazing to include in my project and for me to learn what this process actually looks like on paper.

Thanks so much in advance.

Code:

L = (y2 - y1) / (x2 - x1)
x3 = L^2 - x1 - x2
y3 = L(x1 - x3) - y1

y2 - y1 = 94553076844452666078538149424419144783741135675920254371088167625192913487275
x2 - x1 = 75694105346914480362575934586442506821074289349400393707630734405845016901087
1 / (x2 - x1) = 57109544797366026611537207709745816878454354988638946088653096565731074851657
L = 26260209610829739695182151635707675950033180086458470318530731088353219693361
L^2 = 85396884292048511216639145930585800795235676868516676403763378131573495159908
x3 = 22299113221787846994488776168920263850616409616156953345645360922861305118563
x1 - x3 = 87194808877201440358869426427379159064426064000963275369055864486481116123229
L(x1 - x3) = 114457103505967127914246148065726475976734011734324777350232007537745534737470
y3 = 4557556935953335244676085823642666982350217411134294760123069603436116216826