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In this paper, we study the security of a compressed sensing (CS) based cryptosystem called a sparse one-time sensing (S-OTS) cryptosystem, which encrypts a plaintext with a sparse measurement matrix. To construct the secret matrix and renew it at each encryption, a bipolar keystream and a random permutation pattern are employed as cryptographic primitives, which can be obtained by a keystream generator of stream ciphers. With a small number of nonzero elements in the measurement matrix, the S-OTS cryptosystem achieves efficient CS encryption in terms of memory and computational cost. In security analysis, we show that the S-OTS cryptosystem can be indistinguishable as long as each plaintext has constant energy, which formalizes computational security against ciphertext only attacks (COA). In addition, we consider a chosen plaintext attack (CPA) against the S-OTS cryptosystem, which consists of two sequential stages, keystream and key recovery attacks. Against keystream recovery under CPA, we demonstrate that the S-OTS cryptosystem can be secure with overwhelmingly high probability, as an adversary needs to distinguish a prohibitively large number of candidate keystreams. Finally, we conduct an information-theoretic analysis to show that the S-OTS cryptosystem can be resistant against key recovery under CPA by guaranteeing that the probability of success is extremely low. In conclusion, the S-OTS cryptosystem can be computationally secure against COA and the two-stage CPA, while providing efficiency in CS encryption.

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The present work aimed to determine the phytoextraction potential of four poplar hybrids when treated with mixed heavy metals, cadmium (Cd), chromium, (Cr), copper (Cu), and zinc (Zn) under greenhouse conditions. Poplar hybrids were treated once with six different concentrations (0, 5, 50, 100, 200, and 500 mg L ¡1) of mixed heavy metals over a period of 3 months, after which the plants were harvested, dried, digested using the aqua regia method and the heavy metal concentrations in the roots, stem, and leaves were determined. Individual heavy metal analysis using ICP-AES of separate heavy metals in plant parts demonstrated higher Zn accumulation in leaves, compared to all other heavy metals. As for Cd, Cr, and Cu the concentration accumulation in the leaves, stem, and roots varied across hybrids. Based on the phytoextraction potential of the four hybrids, hybrid 1 (Eco 28) was determined as a suitable candidate for phytoextraction of multi-contaminated sites, with DN 034 also showing selective phytoextraction potential in the early stages of growth.

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