deriveAesKey function
Implementation
Future<Uint8List> deriveAesKey(Uint8List r) async {
final salt = Uint8List(32);
for (var i = 0; i < salt.length; i++) {
salt[i] = rnd.nextInt(256);
}
final info = utf8.encode('AES-GCM key');
final secretKey = await hkdf.deriveKey(
secretKey: SecretKey(r),
nonce: salt,
info: info,
);
return Uint8List.fromList(await secretKey.extractBytes());
}