682 research outputs found

    An intelligent information forwarder for healthcare big data systems with distributed wearable sensors

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    © 2016 IEEE. An increasing number of the elderly population wish to live an independent lifestyle, rather than rely on intrusive care programmes. A big data solution is presented using wearable sensors capable of carrying out continuous monitoring of the elderly, alerting the relevant caregivers when necessary and forwarding pertinent information to a big data system for analysis. A challenge for such a solution is the development of context-awareness through the multidimensional, dynamic and nonlinear sensor readings that have a weak correlation with observable human behaviours and health conditions. To address this challenge, a wearable sensor system with an intelligent data forwarder is discussed in this paper. The forwarder adopts a Hidden Markov Model for human behaviour recognition. Locality sensitive hashing is proposed as an efficient mechanism to learn sensor patterns. A prototype solution is implemented to monitor health conditions of dispersed users. It is shown that the intelligent forwarders can provide the remote sensors with context-awareness. They transmit only important information to the big data server for analytics when certain behaviours happen and avoid overwhelming communication and data storage. The system functions unobtrusively, whilst giving the users peace of mind in the knowledge that their safety is being monitored and analysed

    A structural analysis of the A5/1 state transition graph

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    We describe efficient algorithms to analyze the cycle structure of the graph induced by the state transition function of the A5/1 stream cipher used in GSM mobile phones and report on the results of the implementation. The analysis is performed in five steps utilizing HPC clusters, GPGPU and external memory computation. A great reduction of this huge state transition graph of 2^64 nodes is achieved by focusing on special nodes in the first step and removing leaf nodes that can be detected with limited effort in the second step. This step does not break the overall structure of the graph and keeps at least one node on every cycle. In the third step the nodes of the reduced graph are connected by weighted edges. Since the number of nodes is still huge an efficient bitslice approach is presented that is implemented with NVIDIA's CUDA framework and executed on several GPUs concurrently. An external memory algorithm based on the STXXL library and its parallel pipelining feature further reduces the graph in the fourth step. The result is a graph containing only cycles that can be further analyzed in internal memory to count the number and size of the cycles. This full analysis which previously would take months can now be completed within a few days and allows to present structural results for the full graph for the first time. The structure of the A5/1 graph deviates notably from the theoretical results for random mappings.Comment: In Proceedings GRAPHITE 2012, arXiv:1210.611

    Extending AES with DH Key-Exchange to Enhance VoIP Encryption in Mobile Networks

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    Recently,the evolution and progress have become significant in the field of information technology and mobile technology, especially inSmartphone applications that are currently widely spreading. Due to the huge developments in mobile and smartphone technologies in recent years, more attention is given to voice data transmission such as VoIP (Voice overIP) technologies– e.g. (WhatsApp, Skype, and Face Book Messenger). When using VoIP services over smartphones, there are always security and privacy concerns like the eavesdropping of calls between the communicating parties. Therefore, there is a pressing need to address these risks by enhancing the security level and encryption methods. In this work, we use scheme to encrypt VoIP channels using (128, 192 & 256-bit) enhanced encryption based on the Advanced Encryption Standard (AES) algorithm, by extending it with the well-known Diffie-Hellman (DH) key exchange method. We have performed a series of real tests on the enhanced (AES-DH) algorithm and compared its performance with the generic AES algorithm. The results have shown that we can get a significant increase in the encryption strength at a very small overhead between 4% and 7% of execution timebetween AES and AEScombine withDH for all scenario which was incurred by added time of encryption and decryption. Our approach uses high security and speed and reduces the voice delay.In dealing with sound transfer process via the internet, we use the SIP server to authenticate the communication process between the two parties. The implementation is done on a mobile device (Which is operated by (Android) system) because it has recently been widely used among different people around the world.اصبحت الثورة والتطور كبيرة حديثاً في حقول تكنولوجيا االتصاالت واليواتف النقالة، وخصوصا في تطبيقات اليواتف الذكية التي تنتشر حاليا بشكل واسع. وتم اعطاء المزيد من االىتمام لنقل البيانات الصوتية مثل تكنولوجيا االتصال عبر بروتكول االنترنت، عمى سبيل المثال: )الواتساب، السكايب، الفيس بوك، والماسنجر(. ويعزى ذلك لمتطور الكبير في تكنولوجيا اليواتف النقالة والذكية في السنوات االخيرة. عند استخدام خدمات االتصال عبر بروتكول االنترنت VoIP ،ىناك مخاوف دائمة حول الحماية والخصوصية كالتجسس عمى المكالمات بين جيات االتصال. ولذلك ىنالك حاجة ماسة لمعالجة ىذه المخاطر عن طريق تحسين مستوى الحماية وطرق التشفير. في ىذا العمل، نستخدم/ نجمع بين اثنتين من الخوارزميات لتشفير قنوات االتصال عبر بروتوكول االنترنت )128 ، 192 ،و 256 بت( عبر خوارزمية AESوتمديدىا عبر طريقة تبادل ديفي ىيممان الرئيسية المعروفة. وقمنا باداء العديد من التجارب الحقيقية عمى DH-AES ، وقمنا بمقارنة ادائيا مع اداء خوارزمية معيار التشفير المتقدم العامة. اظيرت النتائج انو بامكاننا الحصول عمى زيادة كبيرة في قوة التشفير بنسبة صغيرة جدا بين 4 %و7 %من وقت التنفيذ بين AESو DH/AES لجميع السيناريو والتي تم تكبدىا من قبل الوقت المضاف لمتشفير وفك التشفير. يستخدم نيجنا درجة عالية من الحماية والسرعة ويقمل من تأخير الصوت، ونستخدم في التعامل مع عممية نقل الصوت عبر االنترنت Server SIPلتوثيق عممية االتصال بين الجيتين. وتم التنفيذ عمى ىاتف نقال يعمل عمى نظام اندرويد؛ النو استخدم بشكل واسع مؤخرا بين مختمف الناس حول العالم

    SMS-based One-Time Passwords: Attacks and Defense

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    SMS-based One-Time Passwords (SMS OTP) were introduced to counter phishing and other attacks against Internet services such as online banking. Today, SMS OTPs are commonly used for authentication and authorization for many different applications. Recently, SMS OTPs have come under heavy attack, especially by smartphone trojans. In this paper, we analyze the security architecture of SMS OTP systems and study attacks that pose a threat to Internet-based authentication and authorization services. We determined that the two foundations SMS OTP is built on, cellular networks and mobile handsets, were completely different at the time when SMS OTP was designed and introduced. Throughout this work, we show why SMS OTP systems cannot be considered secure anymore. Based on our findings, we propose mechanisms to secure SMS OTPs against common attacks and specifically against smartphone trojans
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