public static DecryptedLoraMessage Decrypt(byte[] data, byte[] key, byte[] iv)
{
// int8 -> sbyte
// uint8 -> byte
// word -> ushort
using (var aes = new AesManaged
{
Mode = CipherMode.ECB,
Padding = PaddingMode.None
})
{
var encryptor = aes.CreateEncryptor(key, iv);
var dataLengte = data.Length - 13;
var blockA = new byte[16];
var work = new byte[dataLengte];
for (var i = 0; i < dataLengte; i++)
{
work[i] = data[i + 9];
}
for (var i = 0; i < dataLengte; i += 16)
{
blockA[0] = 0x01;
blockA[1] = 0x00;
blockA[2] = 0x00;
blockA[3] = 0x00;
blockA[4] = 0x00;
blockA[5] = 0; // 0 for uplink frames 1 for downlink frames;
blockA[6] = data[1]; // LSB devAddr 4 bytes
blockA[7] = data[2]; // ..
blockA[8] = data[3]; // ..
blockA[9] = data[4]; // MSB
blockA[10] = data[6]; // LSB framecounter
blockA[11] = data[7]; // MSB framecounter
blockA[12] = 0x00; // Frame counter upper Bytes}
blockA[13] = 0x00;
blockA[14] = 0x00;
blockA[15] = Convert.ToByte((i >> 4) + 1); // block sequence counter 1..
var ox = Encrypt(encryptor, blockA);
var xor = ox.Select(o => (ushort)o).ToArray();
var k = Math.Min(dataLengte - i, 16);
for (var j = 0; j < k; j++)
{
work[i + j] = (byte)(work[i + j] ^ xor[j]);
}
}
var node = data[1] + (data[2] << 8) + (data[3] << 16) + (data[4] << 24);
var decryptedLoraMessage = new DecryptedLoraMessage
{
Node = node.ToString("X"),
Payload = Encoding.ASCII.GetString(work)
};
return(decryptedLoraMessage);
}
}
public static DecryptedLoraMessage Decrypt(byte[] data, byte[] key, byte[] iv)
{
// int8 -> sbyte
// uint8 -> byte
// word -> ushort
using (var aes = new AesManaged
{
Mode = CipherMode.ECB,
Padding = PaddingMode.None
})
{
var encryptor = aes.CreateEncryptor(key, iv);
var dataLengte = data.Length - 13;
var blockA = new byte[16];
var work = new byte[dataLengte];
for (var i = 0; i < dataLengte; i++)
{
work[i] = data[i + 9];
}
for (var i = 0; i < dataLengte; i += 16)
{
blockA[0] = 0x01;
blockA[1] = 0x00;
blockA[2] = 0x00;
blockA[3] = 0x00;
blockA[4] = 0x00;
blockA[5] = 0; // 0 for uplink frames 1 for downlink frames;
blockA[6] = data[1]; // LSB devAddr 4 bytes
blockA[7] = data[2]; // ..
blockA[8] = data[3]; // ..
blockA[9] = data[4]; // MSB
blockA[10] = data[6]; // LSB framecounter
blockA[11] = data[7]; // MSB framecounter
blockA[12] = 0x00; // Frame counter upper Bytes}
blockA[13] = 0x00;
blockA[14] = 0x00;
blockA[15] = Convert.ToByte((i >> 4) + 1); // block sequence counter 1..
var ox = Encrypt(encryptor, blockA);
var xor = ox.Select(o => (ushort) o).ToArray();
var k = Math.Min(dataLengte - i, 16);
for (var j = 0; j < k; j++)
{
work[i + j] = (byte) (work[i + j] ^ xor[j]);
}
}
var node = data[1] + (data[2] << 8) + (data[3] << 16) + (data[4] << 24);
var decryptedLoraMessage = new DecryptedLoraMessage
{
Node = node.ToString("X"),
Payload = Encoding.ASCII.GetString(work)
};
return decryptedLoraMessage;
}
}
