New Conditional Privacy-preserving Encryption Schemes in Communication Network

Nowadays the communication networks have acted as nearly the most important fundamental infrastructure in our human society. The basic service provided by the communication networks are like that provided by the ubiquitous public utilities. For example, the cable television network provides the distribution of information to its subscribers, which is much like the water or gas supply systems which distribute the commodities to citizens. The communication network also facilitates the development of many network-based applications such as industrial pipeline controlling in the industrial network, voice over long-term evolution (VoLTE) in the mobile network and mixture reality (MR) in the computer network, etc. Since the communication network plays such a vital role in almost every aspect of our life, undoubtedly, the information transmitted over it should be guarded properly. Roughly, such information can be categorized into either the communicated message or the sensitive information related to the users. Since we already got cryptographical tools, such as encryption schemes, to ensure the confidentiality of communicated messages, it is the sensitive personal information which should be paid special attentions to. Moreover, for the benefit of reducing the network burden in some instances, it may require that only communication information among legitimated users, such as streaming media service subscribers, can be stored and then relayed in the network. In this case, the network should be empowered with the capability to verify whether the transmitted message is exchanged between legitimated users without leaking the privacy of those users. Meanwhile, the intended receiver of a transmitted message should be able to identify the exact message sender for future communication. In order to cater to those requirements, we re-define a notion named conditional user privacy preservation. In this thesis, we investigate the problem how to preserve user conditional privacy in pubic key encryption schemes, which are used to secure the transmitted information in the communication networks. In fact, even the term conditional privacy preservation has appeared in existing works before, there still have great differences between our conditional privacy preservation definition and the one proposed before. For example, in our definition, we do not need a trusted third party (TTP) to help tracing the sender of a message. Besides, the verification of a given encrypted message can be done without any secret. In this thesis, we also introduce more desirable features to our redefined notion user conditional privacy preservation. In our second work, we consider not only the conditional privacy of the message sender but also that of the intended message receiver. This work presents a new encryption scheme which can be implemented in communication networks where there exists a blacklist containing a list of blocked communication channels, and each of them is established by a pair of sender and receiver. With this encryption scheme, a verifier can confirm whether one ciphertext is belonging to a legitimated communication channel without knowing the exact sender and receiver of that ciphertext. With our two previous works, for a given ciphertext, we ensure that no one except its intended receiver can identify the sender. However, the receiver of one message may behave dishonest when it tries to retrieve the real message sender, which incurs the problem that the receiver of a message might manipulate the origin of the message successfully for its own benefit. To tackle this problem, we present a novel encryption scheme in our third work. Apart from preserving user conditional privacy, this work also enforces the receiver to give a publicly verifiable proof so as to convince others that it is honest during the process of identifying the actual message sender. In our forth work, we show our special interest in the access control encryption, or ACE for short, and find this primitive can inherently achieve user conditional privacy preservation to some extent. we present a newly constructed ACE scheme in this work, and our scheme has advantages over existing ACE schemes in two aspects. Firstly, our ACE scheme is more reliable than existing ones since we utilize a distributed sanitizing algorithm and thus avoid the so called single point failure happened in ACE systems with only one sanitizer. Then, since the ciphertext and key size of our scheme is more compact than that of the existing ACE schemes, our scheme enjoys better scalability

Effect of Diet Supplemented With Rapeseed Meal or Hydrolysable Tannins on the Growth, Nutrition, and Intestinal Microbiota in Grass Carp (Ctenopharyngodon idellus)

Grass carp (Ctenopharyngodon idellus; n = 320) were received four different diets for 56 days. The experimental diets were: fishmeal (FM) containing 10% fishmeal (without rapeseed meal), and rapeseed meal (RM) containing 50% rapeseed meal (without fishmeal), and two semi-purified diets either without (T0) or with 1.25% (T1) supplemental hydrolysable tannin. The approximate content of tannin in the RM diet was 1.31%, which was close to that of T1, while the tannin content of FM was close to that of T0. The weight gain rate of grass carp of the RM group was significantly lower than that of the FM group, while the feeding conversion ratio and the feeding rate were significantly higher in the T1 group than in T0. The muscle lipid content was significantly lower in RM than in FM, while T1 was lower than T0. Intestinal activities of trypsin and α-amylase were significantly higher in T1 and RM groups compared with the other treatments. The hepatic activities of aspartate aminotransferase and alanine aminotransferase were lower in T1 and RM groups compared with the other treatments, while hepatic glycogen, and malonaldehyde were significantly higher in T1 and RM groups. In serum, the total protein and globulin contents were significantly higher in T1 and RM groups, while albumin was significantly lower in the RM group compared to the FM group. High-throughput sequencing showed that Proteobacteria, Firmicutes, and Actinobacteria were the dominant bacterial phyla among groups. The intestinal microbial diversity was higher in T1 and RM. Redundancy analysis showed that tannin, rapeseed meal, and intestinal trypsin activity were positively or negatively correlated with the relative abundance of several different intestinal microbiota at phylum and/or genus levels. The results indicated that 1.25% tannin could not be the main reason for the poor growth of grass carp of the RM group; however, the protein metabolism was disturbed, the absorption of carbohydrate was improved, and the accumulation of lipid had decreased. Furthermore, tannin and rapeseed meal supplementations modulated the intestinal microbiota, and may sequentially regulate the intestinal function by fermenting dietary nutrition, producing digestive enzymes, and modulating probiotics

Quasi-Floquet prethermalization in a disordered dipolar spin ensemble in diamond

Floquet (periodic) driving has recently emerged as a powerful technique for engineering quantum systems and realizing non-equilibrium phases of matter. A central challenge to stabilizing quantum phenomena in such systems is the need to prevent energy absorption from the driving field. Fortunately, when the frequency of the drive is significantly larger than the local energy scales of the many-body system, energy absorption is suppressed. The existence of this so-called prethermal regime depends sensitively on the range of interactions and the presence of multiple driving frequencies. Here, we report the observation of Floquet prethermalization in a strongly interacting dipolar spin ensemble in diamond, where the angular dependence of the dipolar coupling helps to mitigate the long-ranged nature of the interaction. Moreover, we extend our experimental observation to quasi-Floquet drives with multiple incommensurate frequencies. In contrast to a single-frequency drive, we find that the existence of prethermalization is extremely sensitive to the smoothness of the applied field. Our results open the door to stabilizing and characterizing non-equilibrium phenomena in quasi-periodically driven systems.Comment: 7+13 pages, 3+8 figure

Mid-T Heat Treatments on BCPed Coaxial Cavities at TRIUMF

Mid-T heat treatments in the range from 250 to 400 C on superconducting radio-frequency (SRF) cavities have been shown to provide high quality factors that rise with applied rf field strength in high frequency, electro-polished (EP), elliptical cavities operating at 2K, similar to nitrogen doped cavities. The rise in quality factor is attributed to a decrease in the temperature dependent part of the surface resistance $R_{BCS}$. Until now, no results have been reported for these new treatments on quarter-wave resonators (QWR) and half-wave resonators (HWR). The TRIUMF multi-mode coaxial cavities are dedicated test cavities that allow frequency and temperature resolved performance characterization of treatments without changing environments, therefore providing an excellent test vehicle to test these new treatments with rf frequencies ranging from 200 to 1200 MHz. In this paper, performance measurements from both QWR and HWR cavities are reported and their performance compared with four different treatments: baseline, a conventional 120C low temperature bake for 48 hours, and two mid-T bakes at 300 and 400C for 3 hours. In addition, sample analysis using SEM, EDX and SIMS of witness samples is also shown. It is found that the mid-T bakes are not directly transferable to low frequency cavities. In the fundamental modes of the two test cavities, no performance gain over the baseline treatment nor a decreasing temperature dependent component with rising rf amplitude was observed. At frequencies above 1GHz and low temperatures, the mid-T bakes show a reduced field dependence of $R_{BCS}$ compared to both the baseline and 120C treatments

Isotope engineering for spin defects in van der Waals materials

Spin defects in van der Waals materials offer a promising platform for advancing quantum technologies. Here, we propose and demonstrate a powerful technique based on isotope engineering of host materials to significantly enhance the coherence properties of embedded spin defects. Focusing on the recently-discovered negatively charged boron vacancy center ($\mathrm{V}_{\mathrm{B}}^-$) in hexagonal boron nitride (hBN), we grow isotopically purified $\mathrm{h}{}^{10}\mathrm{B}{}^{15}\mathrm{N}$ crystals for the first time. Compared to $\mathrm{V}_{\mathrm{B}}^-$ in hBN with the natural distribution of isotopes, we observe substantially narrower and less crowded $\mathrm{V}_{\mathrm{B}}^-$ spin transitions as well as extended coherence time $T_2$ and relaxation time $T_1$. For quantum sensing, $\mathrm{V}_{\mathrm{B}}^-$ centers in our $\mathrm{h}{}^{10}\mathrm{B}{}^{15}\mathrm{N}$ samples exhibit a factor of $4$ ($2$) enhancement in DC (AC) magnetic field sensitivity. For quantum registers, the individual addressability of the $\mathrm{V}_{\mathrm{B}}^-$ hyperfine levels enables the dynamical polarization and coherent control of the three nearest-neighbor ${}^{15}\mathrm{N}$ nuclear spins. Our results demonstrate the power of isotope engineering for enhancing the properties of quantum spin defects in hBN, and can be readily extended to improving spin qubits in a broad family of van der Waals materials.Comment: 8+4+8 pages, 4+4+6 figure

Integrated Genomic Analysis of the Ubiquitin Pathway across Cancer Types

Protein ubiquitination is a dynamic and reversibleprocess of adding single ubiquitin molecules orvarious ubiquitin chains to target proteins. Here,using multidimensional omic data of 9,125 tumorsamples across 33 cancer types from The CancerGenome Atlas, we perform comprehensive molecu-lar characterization of 929 ubiquitin-related genesand 95 deubiquitinase genes. Among them, we sys-tematically identify top somatic driver candidates,including mutatedFBXW7with cancer-type-specificpatterns and amplifiedMDM2showing a mutuallyexclusive pattern withBRAFmutations. Ubiquitinpathway genes tend to be upregulated in cancermediated by diverse mechanisms. By integratingpan-cancer multiomic data, we identify a group oftumor samples that exhibit worse prognosis. Thesesamples are consistently associated with the upre-gulation of cell-cycle and DNA repair pathways, char-acterized by mutatedTP53,MYC/TERTamplifica-tion, andAPC/PTENdeletion. Our analysishighlights the importance of the ubiquitin pathwayin cancer development and lays a foundation fordeveloping relevant therapeutic strategies