Feature Request: Public Key Derivation Function for BLS12381G2

[Dtitkaio]

Hi MATTR team! 👋

First, thank you for maintaining this fantastic library. The BBS+ signature implementation has been incredibly valuable for our SSI projects.

Context:
We're building a key management system using your library, and we've found ourselves in an interesting situation. While generateBls12381G2KeyPair() works great for new keys, we're looking for a way to handle key import scenarios where we need to derive public keys from existing private keys.

Current Workflow:

// This works great for new keys!
const keyPair = await generateBls12381G2KeyPair();

Desired Enhancement:
Would it be possible to add a utility function for deriving public keys from private keys? Something like:

// Potential API
const publicKey = await derivePublicKeyFromPrivate(existingPrivateKey);

Use Cases:

• Key recovery scenarios where only the private key is available
• Integration with existing key management systems
• Supporting key import/export functionality in SSI wallets

We'd love to contribute to this effort if you're open to it! Let us know if you'd like us to:

• Draft a proposal for the API design
• Help with implementation
• Write tests
• Provide additional use cases or requirements

Thanks for considering this request! Let us know if you need any clarification or additional information.