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There is a elliptic curve with parameters:

a = 0xb3b04200486514cb8fdcf3037397558a8717c85acf19bac71ce72698a23f635
b = 0x12f55f6e7419e26d728c429a2b206a2645a7a56a31dbd5bfb66864425c8a2320

Also the prime number is:

q = 0x247ce416cf31bae96a1c548ef57b012a645b8bff68d3979e26aa54fc49a2c297

How can I solve the equation P * 65537 = H and obtain the value of P?

P and H are points and H equals to (72782057986002698850567456295979356220866771008308693184283729159903205979695, 7766776325114464021923523189912759786515131109431296018171065280757067869793).

Note that in the equation we have Elliptic curve point multiplication!

9yte
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  • 16 point doublings and one addition. Please keep in mind that this is probably too broad for the Stack Exchange Q&A format. A good beginners book on elliptic curves should give you an idea how exactly you calculate it. – Artjom B. Oct 02 '16 at 17:26
  • It looks like you must solve an elliptic curve discrete log to get P, no? If the parameters are too big, this won't be feasible. – mikeazo Oct 02 '16 at 19:33
  • I don't think it is ECDLP, because ECDLP assumes that the points are public and the scalar is secret. – TheGreatContini Oct 02 '16 at 21:26

1 Answers1

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You need to know the number of points on the curve to solve this. Let's call that number n. Then you will have to compute the inverse of 65537 modulo n and do a scalar multiply of your point H by that number.

TheGreatContini
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