[Feature]: Generalize Signing Methods in the catalyst_cardano_serialization package.

[ilap]

Feature Title

Generalize Signing Methods and Support Custom Signing in catalyst_cardano_serialization

Feature Description

The current implementation of the catalyst_cardano_serialization package includes a hard-coded signing method that limits the flexibility for developers to use third-party signing implementations.
This constraint can be overcome by introducing abstract interfaces for signing-related functionality, such as public, private keys, and signature-s.

The proposal is to implement design patterns like the Adapter pattern to decouple the signing process from the package and allow custom implementations. This will improve the extensibility of the package by allowing developers to plug in their own signing logic without modifying the core library.

Proposed Enhancements:

Generalize Signing Methods:

Introduce similar interfaces for handling signing processes. For example:

abstract interface class Signature {
}

abstract interface class Signer {
  Signature sign(List<int> message);
}

abstract interface class Verifier {
  bool verify(Signature signature);
}

This will provide developers with the flexibility to implement custom signing methods for different use cases.

Maintain Compatibility with CBOR:

Ensure the generalized signing methods remain compatible with the existing CBOR encoding/decoding logic by continuing to use CborEncodable, which has been introduced in #696.

Use Case

The proposed changes will make the catalyst_cardano_serialization package more flexible and adaptable to different signing implementations, enabling developers, 3rd party wallet-integrators, etc. to use custom signing mechanisms alongside the current transaction encoding framework.

Is this a modification to an existing feature?

Yes