What ecliptics curve does MobileCoin using?

Hi, what ecliptics curve does MobileCoin using? Is Ed25519 or others?

Why not use secp256k1 like Bitcoin?

Looks like Ed25519 to me…

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Our view is that ed25519 is the superior technical choice.

https://exonum.com/blog/09-27-17-digital-signature/ provides a good explanation.

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For anyone who reading this post, I concluded some main benefits to use Ed25519 instead of Secp256k1:

  • The curve is complete (computations on the curve has no exceptional cases)
  • ~30% faster
  • slightly smaller keys and signatures
  • immune to side-channel attacks
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When you describe the curve as complete, are you referring to it being a prime order group or some other property?

Cheers,
Joshua

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Yes, I think it is about some group operations, but I’m not sure. :slightly_smiling_face: It just digested from the exonum’s blog post.

Ed25519 is a particular instantiation of the next-gen EdDSA signing algorithm. EdDSA uses twisted Edwards curves instead of Weierstrass ones. There are advantages of using Edwards curves: they are complete (that is, computations on Edwards curves have no exceptional cases) and fast (the average performance is ~1.5 times higher than performance on Weierstrass curves). Edwards curves are currently being studied to create post-quantum digital signature schemes.

Ahh yeah sure I see. I think it would be more accurate to say that there are no known exception cases of the Edwards curves. It’s always possible there’s some math hiding somewhere that could invalidate our assumptions.

Cheers,
Joshua

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