generateDiffieHelllman = (publicKey, secretKey) => {
  return ed2curve.convertKeyPair({
    publicKey: publicKey,
    secretKey: new Uint8Array(secretKey),
  });
}
Generate Diffie-Hellman keys
publicKey is a Uint8Array
secretKey is a Uint8Array
Returns { publicKey: Uint8Array, secretKey: Uint8Array }