Add support for Ed25519 key generation

Fixes #6

Add support for Ed25519 key generation in the MPVSS implementation.

* **src/mpvss.rs**
  - Import `ed25519_dalek` crate for Ed25519 key generation.
  - Add `KeyAlgorithm` enum to represent key generation algorithms.
  - Update `MPVSS` struct to include `key_algorithm` field.
  - Add `generate_ed25519_keypair` function to generate Ed25519 key pairs.
  - Update `generate_private_key` and `generate_public_key` functions to support both original and Ed25519 algorithms.

* **README.md**
  - Update "Initialization" section to include Ed25519 key generation.
  - Add a note about Ed25519 key generation in the "In the futures" section.

* **tests/mpvss_tests.rs**
  - Add `test_ed25519_key_generation` function to verify Ed25519 key generation.

---

For more details, open the [Copilot Workspace session](https://copilot-workspace.githubnext.com/AlexiaChen/mpvss-rs/issues/6?shareId=XXXX-XXXX-XXXX-XXXX).

README.md

@@ -54,6 +54,14 @@ p2.initialize();
 p3.initialize();
 ```
 
+To generate Ed25519 key pairs, you can use the `generate_ed25519_keypair` function:
+
+```rust
+use ed25519_dalek::{Keypair, PublicKey, SecretKey, Signature, Signer};
+
+let (secret_key, public_key) = generate_ed25519_keypair();
+```
+
 #### Distribution & Verification
 
 The dealer splits the secret into shares, encrypts them and creates a proof so that everybody can verify that the shares (once decrypted) can be used to reconstruct the secret. The threshold determines how many shares are necessary for the reconstruction. The encrypted shares and the proof are then bundled together.
@@ -143,6 +151,8 @@ assert_eq!(secret_message.clone(), r3_str);
 
 Add more Elliptic Curves groups.
 
+Note: Ed25519 key generation is now supported.
+
 ## Related References:
 
 - Berry Schoenmakers. [A Simple Publicly Verifiable Secret Sharing Scheme and its Application to Electronic Voting](https://www.win.tue.nl/~berry/papers/crypto99.pdf)
@@ -168,4 +178,4 @@ Because the ploynomial commitments does not Pedersen commitment and DLEQ is only
 ## License
 Dual-licensed to be compatible with the Rust project.
 
-Licensed under the Apache License, Version 2.0 [http://www.apache.org/licenses/LICENSE-2.0](http://www.apache.org/licenses/LICENSE-2.0) or the MIT license [http://opensource.org/licenses/MIT](http://opensource.org/licenses/MIT), at your option. This file may not be copied, modified, or distributed except according to those terms.
+Licensed under the Apache License, Version 2.0 [http://www.apache.org/licenses/LICENSE-2.0](http://www.apache.org/licenses/LICENSE-2.0) or the MIT license [http://opensource.org/licenses/MIT](http://opensource.org/licenses/MIT), at your option. This file may not be copied, modified, or distributed except according to those terms.