public CalculatedMIC(DataMessage dataMessage, byte[] nwkSKey, int fCntMsbSeed)
{
if (nwkSKey != null && nwkSKey.Length == 16)
{
CryptoService crypto = new CryptoService();
B0Message b0msg = new B0Message(dataMessage)
{
FCntMSB = fCntMsbSeed
};
for (int i = 0; i <= ushort.MaxValue; i++)
{
byte[] fullCAMC = crypto.AESCMAC(nwkSKey, b0msg.Data);
if (fullCAMC.AsSpan(0, 4).SequenceCompareTo(dataMessage.Parent.Mic.RawData) == 0)
{
FCntMSB = b0msg.FCntMSB;
RawData = fullCAMC.AsSpan(0, 4).ToArray();
IsValid = true;
return;
}
b0msg.FCntMSB = (b0msg.FCntMSB + 1) & 0xFFFF;
}
}
RawData = Array.Empty <byte>();
IsValid = false;
}
/// <summary>
///
/// </summary>
/// <param name="joinAcceptMessage"></param>
/// <param name="appKey"></param>
public CalculatedMIC(JoinAcceptMessage joinAcceptMessage, byte[] appKey)
{
if (appKey != null && appKey.Length == 16)
{
CryptoService crypto = new CryptoService();
// cmac = aes128_cmac(AppKey, MHDR | AppNonce | NetID | DevAddr | DLSettings | RxDelay | CFList)
// MIC = cmac[0..3]
byte[] data = new byte[joinAcceptMessage.RawData.Length + 1];
joinAcceptMessage.Parent.Mhdr.RawData.CopyTo(data.AsSpan()); // [1]
joinAcceptMessage.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;
}
}
