LoadKey.cs

// Headers e.g.

// string header2048 = "0602000000A40000525341310008000001000100";

private byte[] CreatePublicKey(byte[] publicKey)
{
    byte[] publicKey = new byte[publicKey.Length];
    byte[] header = null;

    foreach (KeyValuePair<int, string> keyPair in headersList)
    {
        if (keyPair.Key == keySize)
            header = ASCIIToBcd(Encoding.Default.GetBytes(keyPair.Value));
    }
            
    return publicKey
}

public static byte[] ASCIIToBcd(byte[] ASCII)
{
    byte[] result = new byte[ASCII.Length / 2];
    int i, j;

    j = 0;

    for (i = 0; i < ASCII.Length; i++)
    {
        if ((i % 2) == 0)
            result[j] = (byte)(ASCIIToInt(ASCII[i]) << 4);
        else
        {
            result[j] += (byte)(ASCIIToInt(ASCII[i]));
            j++;
        }
   }

   return result;
}

public static int ASCIIToInt(byte input)
{
    if (input >= '0' && input <= '9')
        return input - 48;
    else if (input >= 'A' && input <= 'F')
        return input - 55;
    else if (input >= 'a' && input <= 'f')
        return input - 87;

    return 0;
}