//*** 20200524 - This one needs to be checked for consistency with Dart code!
public static byte[] encryptStringWithAesGCM(String data, KeyParameter key)
{
// Generate a random 96-bit nonce N
byte[] nonce = KeysHelper.generateRandomNonceUtf8(12);
GcmBlockCipher cipher = new GcmBlockCipher(new AesEngine());
//*** 20200524 - Is 96 the right number?
AeadParameters parameters = new AeadParameters(key, 96, nonce);
cipher.Init(true, parameters);
byte[] utf8Data = Encoding.UTF8.GetBytes(data);
int bufSize = utf8Data.Length;
byte[] cipherText = new byte[cipher.GetOutputSize(bufSize)];
int len = cipher.ProcessBytes(utf8Data, 0, bufSize, cipherText, 0);
cipher.DoFinal(cipherText, len);
using (MemoryStream combinedStream = new MemoryStream())
{
using (BinaryWriter binaryWriter = new BinaryWriter(combinedStream))
{
binaryWriter.Write(nonce);
binaryWriter.Write(cipherText);
}
return(combinedStream.ToArray());
}
}