encryptPKid function
Implementation
Future<String> encryptPKid(String json, Uint8List bobPublicKey) async {
Uint8List message = base64.decode(json);
Uint8List publicKey = Sodium.cryptoSignEd25519PkToCurve25519(bobPublicKey);
Uint8List encryptedData = Sodium.cryptoBoxSeal(message, publicKey);
return base64.encode(encryptedData);
}