Roshan G. Ragel

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Reliability in embedded processors can be improved by control flow checking and such checking can be conducted using software or hardware. Proposed software-only approaches suffer from significant code size penalties, resulting in poor performance. Proposed hardware-assisted approaches are not scalable and therefore cannot be implemented in real embedded(More)
Security and reliability in processor based systems are concernsrequiring adroit solutions.Securityis often compromised by code injection attacks, jeopardizing even `trusted software'.Reliabilityis of concern where unintended code is executed in modern processors with ever smaller feature sizes and low voltage swings causing bit flips. Countermeasures by(More)
AES, Advanced Encryption Standard, is a symmetric key encryption standard being widely used to secure data in places where data confidentiality is a critical issue. AES was adopted from the Rijndael algorithm which was developed by Joan Daemen and Vincent Rijmen. In 2001 NIST, National Institute of Standards and Technology, declared Rijndael algorithm as(More)
Side channel attacks are becoming a major threat to the security of embedded systems. Countermeasures proposed to overcome Simple Power Analysis (SPA) and Differential Power Analysis (DPA), are data masking, table masking, current flattening, circuitry level solutions, dummy instruction insertions and balancing bit-flips. All these techniques are either(More)
Checkpoint and Recovery (CR) allows computer systems to operate correctly even when compromised by transient faults. While many software systems and hardware systems for CR do exist, they are usually either too large, require major modifications to the software, too slow, or require extensive modifications to the caching schemes. In this paper, we propose a(More)
One of the security issues in embedded system is the ability of an adversary to perform side channel attacks. Power analysis attacks are often very successful, where the power sequence dissipated by the system is observed and analyzed to predict secret keys. In this paper we show a processor architecture, which automatically detects the execution of the(More)
Side channel attackers observe external manifestations of internal computations in an embedded system to predict the encryption key employed. The ability to examine such external manifestations (power dissipation or electromagnetic emissions), is a major threat to secure embedded systems. This paper proposes a secure multiprocessor architecture to prevent(More)
Numerous methods have been described in research literature with methods to improve reliability of processors by the use of control-flow checking. High performance and code-size penalties cripple the proposed software approaches, while hardware approaches are not scalable and are thus rarely implemented in real embedded systems. In this article, we show(More)
Multiple string matching is known as locating all the occurrences of a given number of patterns in an arbitrary string. It is used in bio-computing applications where the algorithms are commonly used for retrieval of information such as sequence analysis and gene/protein identification. Extremely large amount of data in the form of strings has to be(More)
Using computers to answer natural language questions is an interesting and challenging problem. Generally such problems are handled under two categories: open domain problems and close domain problems. This paper presents a system that attempts to solve close domain problems. Typically, in a close domain, answers to questions are not available in the public(More)