mGuard

Design:

We should encrypt a data point with all of its attributes, including context, such as location and activity. The context attribute is obtained from the respective lookup table. Basically, each attribute in the lookup table has its corresponding window (see table below). So, for each data point, we obtain the attribute such that the timestamp of the data point falls within the window of the lookup table

snippet of /ndn/org/md2k/mperf/dd40c/data_analysis/gps_episodes_and_semantic_location
+-------------------+-------------------+-----+-------+------------------------------------------+-------------+
|timestamp          |localtime          |user |version|window                                    |semantic_name|
+-------------------+-------------------+-----+-------+------------------------------------------+-------------+
|1993-05-01 10:00:00|1993-05-01 15:00:00|dd40c|1      |{1993-05-01 10:00:00, 1993-05-01 10:01:00}|gym          |
|1993-05-01 10:01:00|1993-05-01 15:01:00|dd40c|1      |{1993-05-01 10:01:00, 1993-05-01 10:02:00}|work         |
|1993-05-01 10:02:00|1993-05-01 15:02:00|dd40c|1      |{1993-05-01 10:02:00, 1993-05-01 10:03:00}|home         |
|.....
+-------------------+-------------------+-----+-------+------------------------------------------+-------------+

We need to get context attributes from all possible lookup tables, semantic location, activity, and so on.

However, right now, lookup table for gps_episodes_and_semantic_location is only available. Meaning, for the context attribute, only the semantic location attribute is used to encrypt the data.

ref: https://github.com/dulalsaurab/new-mguard/blob/master/src/server/data-adapter.cpp#L241-L248