Joydip Mitra

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This work presents a cryptanalytic methodology of the well-known "Optimal Differential Energy Watermarking (DEW)" scheme. The DEW scheme divides the image into some disjoint regions (each region containing two subregions). In the DEW scheme, the watermark is a secret binary string where each individual bit information gets inserted in one of the regions by(More)
Stream cipher Hiji-Bij-Bij (HBB) was proposed by Sarkar at Indocrypt'03. This cipher uses cellular automata (CA). The algorithm has two modes: a basic mode (B) and a self-synchronizing mode (SS). This article presents the first attack on B mode of HBB using 128 bit secret key. This is a known-pliantext guess-then-determine attack. The main step in the(More)
Circulant matrices with general shift by k places have been studied in the literature and formula for their eigenvalues is known. We first reestablish this formula and some further properties of these eigenvalues in a manner suitable for our use. We then consider random k = k(n) circulants A k,n with n → ∞ and whose input sequence {a i } is independent with(More)
Electrically active native point defects have a significant impact on the optical and electrical properties of ZnO nanostructures. Control of defect distribution and a detailed understanding of their physical properties are central to designing ZnO in novel functional forms and architecture, which ultimately decides device performance. Defect control is(More)
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