Score:0

Is it possible to get the x point of the secp256k1 elliptic curve knowing only the y point

br flag

There is a list where, using the coordinates of the x points, it was determined whether there are points in the curve

Here's a link

It can be seen that the generator according to the formula y ^ 2 = x ^ 3 + a * x + b determined from the list GPoint = (Gx, Gy) # Generator Point

a= 0

b= 7

p= 115792089237316195423570985008687907853269984665640564039457584007908834671663


y^2 = x^3 + a * x + b # secp256k1

point   (x,y)

point   (1,29896722852569046015560700294576055776214335159245303116488692907525646231534)

point   (2,69211104694897500952317515077652022726490027694212560352756646854116994689233)

point   (3,94471189679404635060807731153122836805497974241028285133722790318709222555876)

point   (4,40508090799132825824753983223610497876805216745196355809233758402754120847507)

point   (5,0)

point   (6,19112057249303445409876026535760519114630369653212530612662492210011362204224)

point   (7,0)

point   (8,91736135629086734185706894124002126994554994840140056297753929940646699135966)

point   (9,0)

point   (10,0)

.......
.......
.......
.......
etc

But I, on the contrary, need to determine by the list through the point y

that is

point (y, x)

Is it possible to do this?

fgrieu avatar
ng flag
This looks like a CTF. What have you done? Hint: it's algebra [in finite field](https://en.wikipedia.org/wiki/Finite_field) $\mathbb F_p$. Many of the algebra techniques you learned to solve equations in the field $\mathbb R$ work, and here $a=0$ will make it easy. When it comes to inverting $z\mapsto z^3$ in this field, [Fermat's Little Theorem](https://en.wikipedia.org/wiki/Fermat%27s_little_theorem) comes to the rescue.
mangohost

Post an answer

Most people don’t grasp that asking a lot of questions unlocks learning and improves interpersonal bonding. In Alison’s studies, for example, though people could accurately recall how many questions had been asked in their conversations, they didn’t intuit the link between questions and liking. Across four studies, in which participants were engaged in conversations themselves or read transcripts of others’ conversations, people tended not to realize that question asking would influence—or had influenced—the level of amity between the conversationalists.