It is unlikely that a hacker is able to compromise sensitive data that is stored in an encrypted form. However, when data is to be processed, it has to be decrypted, becoming vulnerable to attacks. Homomorphic encryption fixes this vulnerability by allowing one to compute directly on encrypted data. In this survey, both previous and current Somewhat Homomorphic Encryption (SHE) schemes are reviewed, and the more powerful and recent Fully Homomorphic Encryption (FHE) schemes are comprehensively studied. The concepts that support these schemes are presented, and their performance and security are analyzed from an engineering standpoint.

A photocatalyst based on CuO/SiO 2 was prepared, and evaluated for the degradation of methylene blue in aqueous medium. The photocatalyst was obtained by calcination method of copper salt, in the presence of silica. The characterization by XRD, FTIR, and TPR techniques confirmed the formation of CuO as active phase. SEM studies showed CuO deposited on the surface of SiO 2 . By ESI-MS, it was demonstrated that the degradation of methylene blue occurs through successive hydroxylations. Photodegradation assays showed that CuO/SiO 2 was efficient for degradation, and that the material worked better in the presence of UV light.

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The Cloud-Edges (CE) framework, wherein small groups of Internet of Things (IoT) devices are serviced by local edge devices, enables a more scalable solution to IoT networks. The trustworthiness of the network may be ensured with Trusted Platform Modules (TPMs). This small hardware chip is capable of measuring and reporting a representation of the state of an IoT device. When connecting to a network, the IoT platform might have its state signed by the TPM in an anonymous way to prove both its genuineness and secure state through the Direct Anonymous Attestation (DAA) protocol. Currently standardised DAA schemes have their security supported on the factoring and discrete logarithm problems. Should a quantum-computer become available in the next few decades, these schemes will be broken. There is therefore a need to start developing a post-quantum DAA protocol. This paper presents a Lattice-based DAA (LDAA) scheme to meet this requirement. The security of this scheme is proved in the Universally Composable (UC) security model under the hardness assumptions of the Ring Inhomogeneous Short Integer Solution (Ring-ISIS) and Ring Learning With Errors (Ring-LWE) problems. Compared to the only other post-quantum DAA scheme available in related art, the storage requirements of the TPM are reduced twofold and the signature sizes 5 times. Moreover, experimental results show that the signing and verification operations are accelerated 1.1 and 2.0 times, respectively.

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Sign detection is a widely used operation, namely in digital fixed-point signal processing, but hard to perform in residue number systems (RNSs). Presented is an effective method for performing RNS sign identification in the comprehensive extended 3-moduli set {2 n − 1, 2 n + k , 2 n + 1}, which covers from the traditional 3-moduli set, for k = 0, up to the set whose binary channel width is 2n (k = n). The proposed method is applied to design an efficient hardware architecture for sign detection that not only takes advantage of the arithmetic units available in the RNS, but also imposes a small overhead, both in terms of cost and performance. Experimental results for a 65 nm CMOS technology show that the proposed architecture supersedes the related state-of-the-art, requiring < 40% of circuit area, reducing the imposed delay by about 25%, and the power consumption by 30%.

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