private byte[] GenerateDerivationData(SessionKeyType sessionKeyType)
{
var data = new List <byte> {
0x01, (byte)sessionKeyType
};
data.AddRange(this.SequenceCounter);
data.AddRange(Enumerable.Repeat <byte>(0x00, 12));
return(data.ToArray());
}
// don't work with CFLIST atm
private static byte[] CalculateKey(SessionKeyType type, AppNonce appNonce, NetId netId, DevNonce devNonce, AppKey appKey)
{
using var aes = Aes.Create("AesManaged");
var rawAppKey = new byte[AppKey.Size];
_ = appKey.Write(rawAppKey);
aes.Key = rawAppKey;
#pragma warning disable CA5358 // Review cipher mode usage with cryptography experts
// Cipher is part of the LoRaWAN specification
aes.Mode = CipherMode.ECB;
#pragma warning restore CA5358 // Review cipher mode usage with cryptography experts
aes.Padding = PaddingMode.None;
var buffer = new byte[1 + AppNonce.Size + NetId.Size + DevNonce.Size + 7];
var pt = buffer.AsSpan();
Debug.Assert(pt.Length == 16);
pt[0] = unchecked ((byte)type);
pt = pt[1..];
private byte[] GenerateSessionKey(SessionKeyType sessionKeyType, byte[] staticKey) => TripleDES.Encrypt(this.GenerateDerivationData(sessionKeyType), staticKey);