Mutual Authentication Protocols for RFID Systems

Radio-Frequency Identification Devices (RFID) is emerging as a pervasive computing technology with numerous applications. Current low-cost RFID tags are highly resource-constrained and cannot support complex security mechanisms. Hence they have potential risks and may violate the privacy of their bearers. The challenge in providing security for low-cost RFID tags lies in that they are computationally weak devices, unable to perform even basic symmetric-key cryptographic operations as proposed in currently available protocols. In this thesis we have analyzed the security issues and requirements for a RFID system. We have proposed a suite of lightweight mutual authentication protocols for low-cost RFID tags which offer an adequate level of security at much reduced cost. We also compare our proposed protocols with those proposed by others. Furthermore we apply our proposed protocol to secure a supply chain management system.Computer Science Departmen

Hepatocellular carcinoma in Native South Asian Pakistani population; trends, clinico-pathological characteristics & differences in viral marker negative & viral-hepatocellular carcinoma

Background HCC is the fifth most common cancer globally. Our study was conducted to (1)investigate the trends and clinico-pathological characteristics of Hepatocellular carcinoma among native South Asian patients in Pakistan, (2)to estimate the prevalence as well as the trends of viral marker negative HCC and (3) to compare the clinico-pathological, radiological characteristics, applicability of treatment at diagnosis and prognostic factors among patients with both viral marker negative and viral marker positive-HCC being consulted at Aga Khan University Hospital(AKUH), Karachi, Pakistan. Method Patients ≥18 years, already diagnosed to have HCC and visiting AKUH during 1999–2009 were identified using ICD code 1550. The diagnosis of HCC was made in the presence of characteristic features of HCC on triple-phasic CT scan/MRI or with histological findings on biopsy. Results 645 patients were enrolled. Of these 546(84.7%) were viral-HCC and 99(15.3%) were viral marker negative HCC. Among viral-HCC group underlying etiology of cirrhosis was HCV in 67.9%, HBV in 21.8% and concomitant HBV with HCV or HDV in 10.3% cases. Majority (62.8%) patients had advanced HCC. Larger tumor size (p \u3c 0.001), shorter duration between diagnosis of cirrhosis and HCC (p 0.03), concomitant Diabetes Mellitus (p \u3c 0.001) were found significant factors associated with viral marker negative HCC. Conclusion The burden of hepatocellular carcinoma is rising among native South Asian Pakistani population and the viral marker negative HCC are not uncommon in our population. Viral marker negative HCC tend not to be under surveillance as compared to viral-HCC and are diagnosed mostly at advanced stage & when they became symptomatic

Highly accurate compact flowfield dependent variation method for solving two-dimensional navier-stokes equations

A higher order accurate method, namely high order compact flowfield dependent variation (HOC-FDV) method, has been developed to solve full Navier-Stokes equations. The scheme is a third order accuracy in time and fourth order accuracy in space. The spatial derivatives in the third order accuracy in time, flowfield dependent variation (FDV) equations proposed by Chung, are approximated using high order compact (HOC) Hermitian (Pade) scheme. The solution procedure at each time step consists of a system of block tri-diagonal matrix which can be solved efficiently in a standard manner. Two-dimensional numerical examples are tested to examine the accuracy and shockwave boundary layer interactions. The results showed the high accuracy and the capability of the higher order scheme to simulate accurately the separation and discontinuit