http://repository.iiitd.edu.in/xmlui/handle/123456789/94 2026-04-11T01:30:24Z http://repository.iiitd.edu.in/xmlui/handle/123456789/111 Android phone based appraisal of app behavior on cell networks Gupta, Shaifali; Garg, Rashi; Jain, Nikita; Naik, Vinayak; Kaul, Sanjit Krishnan The rapid adoption of smartphones has engendered a large ecosystem of mobile data applications. In fact, a large part of mobile tra c is now data and not voice. Many of these applications, for example VoIP clients, stay active in the background. In the background, they may not communi- cate large amounts of data. However, their regular bursts of activity can lead to large signaling overheads, wastage of radio resources, and draining of a phone's battery. Signal- ing overheads can lead to service outage over a large geo- graphical region by overloading the radio network controller (gateway) of the 3G (LTE) network, which is expected to handle signaling from a large number of base stations. In this work we propose for Android smartphones an on-the- phone mechanism to detect background applications that due to bad design (given the network's settings) or their malicious nature (exploiting the network's settings) lead to above mentioned ine ciencies. Speci cally, we propose the metrics of average energy/byte and the average time-to-state- promotion (TSP) after the Radio Resource Control (RRC) enters the IDLE state. The metrics capture an application's e ciency, which is a function of the network's settings of RRC inactivity timeout values and an application's back- ground activity. The e cacy of these metrics is tested on commonly used Android applications. We also outline a fully functional ready-to-install tool that we developed and used for our studies. 2013-10-31T05:07:52Z http://repository.iiitd.edu.in/xmlui/handle/123456789/109 Characterizing mobility patterns of people in developing countries using their mobile phone data Yadav, Kuldeep; Kumar, Amit; Bharti, Aparna; Naik, Vinayak Location data collected from mobile phone users provide an ideal platform to generate human mobility patterns. These patterns give us insights into how people travel in their dayto- day lives.With availability of cellular data, either at large-scale but with low location accuracy or at small-scale but with high location accuracy, studying mobility patterns is now possible. An example of former dataset is CDRs (Call Detail Records) and that of latter is GSM/WiFi/GPS traces collected from mobile phones. So far the studies have been focused on data collected in developed countries. In this paper, we make a first attempt in finding and analyzing mobility patterns of people in developing countries using both the categories of data. We use publicly available CDR data and we collect our own data for capturing fine-grained location. Ours is the first dataset of its kind that is publicly available. We analyze this data to find movement as well as place visiting patterns, compare our findings with existing studies, and discuss their implications. For example, urban people in developing countries travel farther distances in their day to day life as compared to people living in non-urban areas. Also, distance travelled by urban people in developing countries is as much as six times lower compared to developed countries. 2013-10-10T08:52:47Z http://repository.iiitd.edu.in/xmlui/handle/123456789/99 Biclique cryptanalysis of full round AES with reduced data complexity Chang, Donghoon; Ghosh, Mohona; Sanadhya, Somitra Kumar Biclique cryptanalysis was proposed by Bogdanov et al. in Asiacrypt 2011 as a new tool for cryptanalysis of block ciphers. A major hurdle in carrying out biclique cryptanalysis is that it has a very high query complexity (of the order of 288 for AES-128, 280 for AES-192 and 240 for AES-256). This naturally puts a big question mark over the practical feasibility of implementing biclique attack in real world. In this work, we re-evaluate the security of full round AES against biclique cryptanalysis. We describe an alternate biclique construction with signi cantly reduced query complexity (of the order of 224 for AES-128, 232 for AES-192 and 28 for AES-256) at the expense of a slightly increased computational cost. In our approach, we use independent biclique technique to launch a chosen ciphertext attack against AES. 2013-05-31T05:49:40Z