Creating a public/private keypair

Let’s look at various ways of creating public/private keypairs, signing messages and verifying them

EdDSA - Edwards-curve Digital Signature Algorithm  - ED25519

• Using @noble/ed25519

  import * as ed from "@noble/ed25519";
  
  async function main() {
    // Generate a secure random private key
    const privKey = ed.utils.randomPrivateKey();
  
    // Convert the message "hello world" to a Uint8Array
    const message = new TextEncoder().encode("hello world");
  
    // Generate the public key from the private key
    const pubKey = await ed.getPublicKeyAsync(privKey);
  
    // Sign the message
    const signature = await ed.signAsync(message, privKey);
  
    // Verify the signature
    const isValid = await ed.verifyAsync(signature, message, pubKey);
  
    // Output the result
    console.log(isValid); // Should print `true` if the signature is valid
  }
  
  main();

• Using @solana/web3.js

  import { Keypair } from "@solana/web3.js";
  import nacl from "tweetnacl";
  
  // Generate a new keypair
  const keypair = Keypair.generate();
  
  // Extract the public and private keys
  const publicKey = keypair.publicKey.toString();
  const secretKey = keypair.secretKey;
  
  // Display the keys
  console.log("Public Key:", publicKey);
  console.log("Private Key (Secret Key):", secretKey);
  
  // Convert the message "hello world" to a Uint8Array
  const message = new TextEncoder().encode("hello world");
  
  const signature = nacl.sign.detached(message, secretKey);
  const result = nacl.sign.detached.verify(
    message,
    signature,
    keypair.publicKey.toBytes(),
  );
  
  console.log(result);

ECDSA (Elliptic Curve Digital Signature Algorithm) - secp256k1

• Using @noble/secp256k1

  import * as secp from "@noble/secp256k1";
  
  async function main() {
    const privKey = secp.utils.randomPrivateKey(); // Secure random private key
    // sha256 of 'hello world'
    const msgHash =
      "b94d27b9934d3e08a52e52d7da7dabfac484efe37a5380ee9088f7ace2efcde9";
    const pubKey = secp.getPublicKey(privKey);
    const signature = await secp.signAsync(msgHash, privKey); // Sync methods below
    const isValid = secp.verify(signature, msgHash, pubKey);
    console.log(isValid);
  }
  
  main();

• Using ethers

  import { ethers } from "ethers";
  
  // Generate a random wallet
  const wallet = ethers.Wallet.createRandom();
  
  // Extract the public and private keys
  const publicKey = wallet.address;
  const privateKey = wallet.privateKey;
  
  console.log("Public Key (Address):", publicKey);
  console.log("Private Key:", privateKey);
  
  // Message to sign
  const message = "hello world";
  
  // Sign the message using the wallet's private key
  const signature = await wallet.signMessage(message);
  console.log("Signature:", signature);
  
  // Verify the signature
  const recoveredAddress = ethers.verifyMessage(message, signature);
  
  console.log("Recovered Address:", recoveredAddress);
  console.log("Signature is valid:", recoveredAddress === publicKey);