Score:1

How to map point from one EC to another EC?

mk flag

p = 115792089237316195423570985008687907853269984665640564039457584007908834671663

How to map points from curve

E6 = EllipticCurve(GF(p), [0,7])

to

E1 = EllipticCurve(GF(p), [0,n])

n = 1...6

?

Maarten Bodewes avatar
in flag
This looks like a homework assignment. What have you tried? At this site we only give hints in comments, and that's only when enough effort is shown.
Matiy avatar
mk flag
@Maarten Bodewes, I try realise this https://github.com/christianlundkvist/blog/blob/master/2020_05_26_secp256k1_twist_attacks/secp256k1_twist_attacks.md
Marc Ilunga avatar
tr flag
Are you trying to implement the invalid curve attack?
Matiy avatar
mk flag
@Marc Ilunga, yes invalid curve or twist curve.
Marc Ilunga avatar
tr flag
For an invalid curve attack, you are not so much mapping points from a curve to another. The attacker chooses an appropriate point $P$ on the new curve and send this malicious point, and the victim computes $Q = x*P$. But computing $Q$ will simply use the "computation rules" of the malicious curve. The reason, you called $n$ is not needed for computing $Q$. So, the victim is tricked to reveal some information on $x$. Repeat with different $n$ until $x$ can be fully revealed. And this is fixed by verifying that the point received indeed lies on the "secure" curve.
Maarten Bodewes avatar
in flag
@MarcIlunga I guess above may be considered an answer if we assume that the problem stated is an XY-problem (asking for X while we really want to know Y).
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