remove usage of libsecp256k1 for secp256k1 in claims pallet

[Gioyik]

Description

removing the usage of libsecp256k1 from claims pallet as we have moved already to use secp256k1.

Context here: #5840.

Integration

I don't think it requires any integration.

Review Notes

mainly a dependency check, just make sure it behaves in the same way as before.

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[Gioyik]

I will fix this, probably my editor did something, sorry

[Gioyik]

polkadot-sdk/polkadot/runtime/common/src/claims.rs

Line 693 in b121b06

let (sig, recovery_id) = libsecp256k1::sign(&libsecp256k1::Message::parse(&msg), secret);

comes directly from libsecp256k1 and there is no equal in secp256k1 as it looks custom for the lib. Do we still need it or use it? if yes, I can move into the repo (someone can tell me where this could go and be exported by) and figure out the equivalent without using libsecp256k1. I haven't checked how much it would be to move it.

[Gioyik]

actually, I am not sure if the whole secp_utils is even used, it looks it is highly attached to certain parts or behavior in libsecp256k1. Just my early check, I haven't seen in deep.

[bkchr]

comes directly from libsecp256k1 and there is no equal in secp256k1 as it looks custom for the lib. Do we still need it or use it?

You probably need to use k256 as this only compiles to no_std and then use sign_prehash_recoverable

[Gioyik]

@bkchr sorry if I don't follow, sign_prehash_recoverable is in the ecdsa crate, is that what you referring to? k256 crate has a sign_prehash but it seems to work slightly different. sec256k1 has a sign_ecdsa_recoverable function, but doesn't return the same as the one in ecdsa crate.

or maybe you are referring to something inside sp-io I am not aware of 😄