internal static bool verifyChallenger(CosemParameters parameters, CosemConnection connection, byte[] data)
{
if (data == null || data.Length == 0)
{
return(false);
}
try
{
byte[] calculated = new byte[0];
switch (parameters.authenticationType.innerEnumValue)
{
case AuthenticationType.InnerEnum.PUBLIC:
case AuthenticationType.InnerEnum.LLS:
throw new System.InvalidOperationException();
case AuthenticationType.InnerEnum.HLS:
calculated = aes128(connection.challengeServerToClient, parameters.llsHlsSecret);
break;
case AuthenticationType.InnerEnum.HLS_MD5:
calculated = md5(connection.challengeClientToServer, parameters.llsHlsSecret);
break;
case AuthenticationType.InnerEnum.HLS_SHA1:
calculated = sha1(connection.challengeClientToServer, parameters.llsHlsSecret);
break;
case AuthenticationType.InnerEnum.HLS_GMAC:
if (data[0] != SC_AUTHENTICATION)
{
return(false);
}
System.IO.MemoryStream stream = new System.IO.MemoryStream();
stream.WriteByte(SC_AUTHENTICATION);
stream.Write(parameters.ak, 0, parameters.ak.Length);
stream.Write(connection.challengeClientToServer, 0, connection.challengeClientToServer.Length);
//connection.serverInvocationCounter = BitConverter.ToInt32(helper.extensions.copyOfRange(data, 1, 5), 0);
var aux = helper.extensions.copyOfRange(data, 1, 5);
connection.serverInvocationCounter = BitConverter.ToInt32(new byte[] { (aux[3]), (aux[2]), (aux[1]), (aux[0]) }, 0);
data = helper.extensions.copyOfRange(data, 5, data.Length);
CosemParameters cosemParams = new CosemParameters();
cosemParams.setSystemTitle(connection.serverSysTitle);
cosemParams.setEk(parameters.ek);
calculated = Security.aesGcm(new byte[0], stream.ToArray(), cosemParams, connection.serverInvocationCounter);
break;
default:
throw new System.ArgumentException();
}
return(Enumerable.SequenceEqual(data, calculated));
}
catch (IOException)
{
throw new DlmsException(DlmsException.DlmsExceptionReason.INTERNAL_ERROR);
}
}
