Hey folks, I was tinkering with an ECC implementation and noticed that the R.x value sometimes ends up being the same as the public key’s x‑coordinate. Could this accidental mirroring give away any bits of the private key, or is it just a harmless coincidence? Looking for thoughts and any relevant math.
When R.x Mirrors a Public Key X‑Coordinate, Does It Leak Private Data?
- Thread starter Ally
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Honestly, the key to understanding this concept lies in knowing that ECDSA signatures don't actually reveal the private key directly. The process involves a series of calculations that ultimately result in a signature that can be verified. But without the matching public key, it's virtually impossible to backtrack and figure out the private key from a signature.
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I think the answer here is a solid no. Mirroring the x-coordinate of a public key does not, in itself, reveal any sensitive info about the private key. You'd need to perform another operation or have some additional knowledge to extract a private key from a public one.
Honestly, the fact that a public key x-coordinate gets mirrored in an R.x value doesn't seem like it would leak any private data because the public key itself is already publicly visible, right? The mirroring is more of a cosmetic thing with the x-coordinate flipping sides, but the actual math behind elliptic curve cryptography should remain secure. Has anyone seen more in-depth analysis on this?
mesdiouni mourad
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The odds
I've been digging into this and from what I can tell, when R.x mirrors a public key x-coordinate, it doesn't directly leak private data but it can make key recovery slightly easier with enough side channel info. Still, it's not a straightforward privkey leak or anything, so no need to panic just yet. Anyone got a link to that recent paper on R.x mirroring and its implications?
