A Call Data Record (CDR) is a set of information relating to the mobile phone calls, of a mobile user, for a particular period. However, the CDR does not include contents of a telephone conversation or messages exchanged.
The CDR is available with telecom operators. The record contains critically sensitive information such as Mobile Station International Subscriber Directory Numbers (MSISDNs), International Mobile Subscriber Identity (IMSI), International Mobile Equipment Identity (IMEI), and location details of mobile subscribers.
This string of information of the CDR includes details such as the name of the subscriber, the details of calls made by this subscriber during a given period, the duration of each call, whether the call terminated normally or abnormally, location of the caller, location of the call recipient, and such other details.