Use k256 native serde support

[ggutoski]

The next release of k256 will support serde. https://github.com/RustCrypto/elliptic-curves/pull/464 With that we can delete our k256_serde module! 🥳

[tarcieri]

k256 v0.10.0 is out with native serde support:

• https://crates.io/crates/k256/0.10.0
• https://docs.rs/k256/latest/k256/#serde-support

[thor314]

We've forked this library, and updated dependencies. Would you accept a pull request updating them? @ggutoski https://github.com/Entropyxyz/tofn

[ggutoski]

Sure! Happy to take a look. Updating dependencies has been on the to-do list for a while.

[thor314]

alright. Need to clean up a bit, and a pull is on the way.

[thor314]

pull is here https://github.com/axelarnetwork/tofn/pull/203

[tarcieri]

Let me know if you encounter any issues with this. We've had some problems with various serde format implementations.

FWIW we'll be migrating to this in a forthcoming update to the elliptic-curve crate (i.e. v0.12, which will probably be out in the next few months):

https://github.com/RustCrypto/formats/tree/master/serdect

[thor314]

@tarcieri, looks like k256 supports serialization for AffinePoint, Scalar, and VerifyingKey, but not ProjectivePoint. Why is that?

[tarcieri]

@thor314 probably an oversight, although FWIW the implementation would be converting the ProjectivePoint to an AffinePoint and serializing that.

ProjectivePoint is a convenient representation for arithmetic, whereas AffinePoint is more of the "serialization type"

[thor314]

@tarcieri, simple enough. Would it be helpful if I submitted a pull to k256 with that feature?

[tarcieri]

sure, that's fine. however master has the v0.11.0-pre branch of k256 and we don't have separate branches for older versions, so it won't get into k256 until the next release

[thor314]

@tarcieri what branch should I submit the k256 feature to?

[tarcieri]

master