Sikhar Patranabis

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In this paper we propose the first practical fault attack on the time redundancy countermeasure for AES using a biased fault model. We develop a scheme to show the effectiveness of a biased fault model in the analysis of the time redundancy countermeasure. Our attack requires only faulty ciphertexts and does not assume strong adversarial powers. We(More)
Biased fault attacks such as the Differential Fault Intensity Analysis (DFIA) have been a major threat to cryptosystems in recent times. DFIA combines principles of side channel analysis and fault attacks to try and extract the key using faulty ciphertexts only. Biased fault attacks have also been shown to weaken traditional redundancy based(More)
The availability of an overwhelmingly large amount of bibliographic information including citation and co-authorship data makes it imperative to have a systematic approach that will enable an author to organize her own personal academic network profitably. An effective method could be to have one's co-authorship network arranged into a set of ``circles'',(More)
Infective countermeasures have been a promising class of fault attack countermeasures. However, they have been subjected to several attacks owing to lack of formal proofs of security and improper implementations. In this paper, we first provide a formal information theoretic proof of security for one of the most recently proposed infective countermeasures(More)
Side channel analysis and active fault analysis are now major threats to even mathematically robust cryptographic algorithms that are otherwise resistant to classical cryptanalysis. This paper focuses on designing encryption schemes that use secret tweaks to achieve innate security against fault analysis. The paper examines linear and non-linear secret(More)
Side-channel attacks are a potent threat to the security of devices implementing cryptographic algorithms. Designing lightweight countermeasures against side-channel analysis that can run on resource constrained devices is a major challenge. One such lightweight countermeasure is shuffling, in which the designer randomly permutes the order of execution of(More)
Evaluation of side channel vulnerability of a cryptosystem has seen significant advancement in recent years. Researchers have proposed several metrics like Test Vector Leakage Assessment Methodology (TVLA), Normalized Inter Class Variance (NICV), Signal to Noise Ratio (SNR), Guessing Entropy to determine side channel security of cryptoimplementations. Among(More)
The recent advent of cloud computing and the IoT has made it imperative to have efficient and secure cryptographic schemes for online data sharing. Data owners would ideally want to store their data/files online in an encrypted manner, and delegate decryption rights for some of these to users with appropriate credentials. An efficient and recently proposed(More)
We present a new class of public-key predicate encryption schemes that are provably function private in the standard model under well-known cryptographic assumptions, and assume predicate distributions satisfying realistic min-entropy requirements. More concretely, we present public-key constructions for identity-based encryption (IBE) and inner-product(More)
Recent literature has demonstrated that the security of Physically Unclonable Function (PUF) circuits might be adversely affected by the introduction of faults. In this paper, we propose novel and efficient architectures for a variety of widely used delay-based PUFs which are robust against high precision laser fault attacks proposed by Tajik et al. in(More)