Authentication mechanism

Dear Mr. Mikko,

Sorry, the removal of original message was accidental.
My original message was this.
In DLMS_C++ code appreciation, the command line argument for authentication level (-a) can take one of value as None, Low, High, High_Sha1, High_Sha256, High_Gmac.
Is this value to be used is a call from client or it has to be enquired from meter and it has to be used?
Because for meter what we have using for the first time we used -a High and worked directly for Writing RTC operation.
Basically, we wanted to know what authentication mechanism is used by meter for which your answer was need to check with meter manufacture before we use.
The next query was regarding guruX Director.

Thanks,
-Janardhan N L
Dear Mr. Mikko,

Thanks for your inputs. I shall check with meter manufacturer to know the authentication mechanism used.
Actually, in below conversation i had queried authentication mechanism used w.r.t write operation.
In fact, when we used Gurux Director tool we have provided password for HLS for RTC write operation.
Apart from this we have not provided any authentication information in tool, we were able to see successful RTC write operation. In this case, tool is able to clear required authentication process.
By any chance, is tool is using any default authentication mechanism to do required write operation.
If so, which is that mechanism being used?
Can you please clarify?

Thanks,
-Janardhan N L