/// <summary>
///
/// </summary>
/// <param name="joinAcceptMessage"></param>
/// <param name="appKey"></param>
public CalculatedMIC(JoinRequestMessage joinRequestMessage, byte[] appKey)
{
if (appKey != null && appKey.Length == 16)
{
CryptoService crypto = new CryptoService();
// cmac = aes128_cmac(AppKey, MHDR | AppEUI | DevEUI | DevNonce)
// MIC = cmac[0..3]
byte[] data = new byte[joinRequestMessage.RawData.Length + 1];
joinRequestMessage.Parent.Mhdr.RawData.CopyTo(data.AsSpan()); // [1]
joinRequestMessage.RawData.CopyTo(data.AsSpan(1));
byte[] fullCAMC = crypto.AESCMAC(appKey, data);
RawData = fullCAMC.AsSpan(0, 4).ToArray();
IsValid = true;
}
else
{
RawData = Array.Empty <byte>();
IsValid = false;
}
}
