On R\'{e}nyi Differential Privacy in Statistics-Based Synthetic Data Generation

Privacy protection with synthetic data generation often uses differentially private statistics and model parameters to quantitatively express theoretical security. However, these methods do not take into account privacy protection due to the randomness of data generation. In this paper, we theoretically evaluate R\'{e}nyi differential privacy of the randomness in data generation of a synthetic data generation method that uses the mean vector and the covariance matrix of an original dataset. Specifically, for a fixed $\alpha > 1$, we show the condition of $\varepsilon$ such that the synthetic data generation satisfies $(\alpha, \varepsilon)$-R\'{e}nyi differential privacy under a bounded neighboring condition and an unbounded neighboring condition, respectively. In particular, under the unbounded condition, when the size of the original dataset and synthetic datase is 10 million, the mechanism satisfies $(4, 0.576)$-R\'{e}nyi differential privacy. We also show that when we translate it into the traditional $(\varepsilon, \delta)$-differential privacy, the mechanism satisfies $(4.00, 10^{-10})$-differential privacy.Comment: 18 pages, 3 figure

Efficient Noise Generation Protocols for Differentially Private Multiparty Computation

To bound information leakage in outputs of protocols, it is important to construct secure multiparty computation protocols which output differentially private values perturbed by the addition of noise. However, previous noise generation protocols have round and communication complexity growing with differential privacy budgets, or require parties to locally generate non-uniform noise, which makes it difficult to guarantee differential privacy against active adversaries. We propose three kinds of protocols for generating noise drawn from certain distributions providing differential privacy. The two of them generate noise from finite-range variants of the discrete Laplace distribution. For $(\epsilon,\delta)$-differential privacy, they only need constant numbers of rounds independent of $\epsilon,\delta$ while the previous protocol needs the number of rounds depending on $\delta$. The two protocols are incomparable as they make a trade-off between round and communication complexity. Our third protocol non-interactively generates shares of noise from the binomial distribution by predistributing keys for a pseudorandom function. It achieves communication complexity independent of $\epsilon$ or $\delta$ for the computational analogue of $(\epsilon,\delta)$-differential privacy while the previous protocols require communication complexity depending on $\epsilon$. We also prove that our protocols can be extended so that they provide differential privacy in the active setting

3-Party Secure Computation for RAMs: Optimal and Concretely Efficient

A distributed oblivious RAM (DORAM) is a method for accessing a secret-shared memory while hiding the accessed locations. DORAMs are the key tool for secure multiparty computation (MPC) for RAM programs that avoids expensive RAM-to-circuit transformations. We present new and improved 3-party DORAM protocols. For a logical memory of size $N$ and for each logical operation, our DORAM requires $O(\log N)$ local CPU computation steps. This is known to be asymptotically optimal. Our DORAM satisfies passive security in the honest majority setting. Our technique results with concretely-efficient protocols and does not use expensive cryptography (such as re-randomizable or homomorphic encryption). Specifically, our DORAM is 25X faster than the known most efficient DORAM in the same setting. Lastly, we extend our technique to handle malicious attackers at the expense of using slightly larger blocks (i.e., $\omega(\log^2 N)$ vs. $\Omega(\log N)$). To the best of our knowledge, this is the first concretely-efficient maliciously secure DORAM. Technically, our construction relies on a novel concretely-efficient 3-party oblivious permutation protocol. We combine it with efficient non-oblivious hashing techniques (i.e., Cuckoo hashing) to get a distributed oblivious hash table. From this, we build a full-fledged DORAM using a distributed variant of the hierarchical approach of Goldreich and Ostrovsky (J. ACM \u2796). These ideas, and especially the permutation protocol, are of independent interest

Communication-Efficient Inner Product Private Join and Compute with Cardinality

Private join and compute (PJC) is a paradigm where two parties owing their private database securely join their databases and compute a function over the combined database. Inner product PJC, introduced by Lepoint et al. (Asiacrypt\u2721), is a class of PJC that has a wide range of applications such as secure analysis of advertising campaigns. In this computation, two parties, each of which has a set of identifier-value pairs, compute the inner product of the values after the (inner) join of their databases with respect to the identifiers. They proposed inner product PJC protocols that are specialized for the unbalanced setting where the input sizes of both parties are significantly different and not suitable for the balanced setting where the sizes of two inputs are relatively close. We propose an inner product PJC protocol that is much more efficient than that by Lepoint et al. for balanced inputs in the setting where both parties are allowed to learn the intersection size additionally. Our protocol can be seen as an extension of the private intersection-sum protocol based on the decisional Diffie-Hellman assumption by Ion et al. (EuroS&P\u2720) and is especially communication-efficient as the private intersection-sum protocol. In the case where both input sizes are $2^{16}$, the communication cost of our inner-product PJC protocol is $46\times$ less than that of the inner product PJC protocol by Lepoint et al

In Vitro Studies to Define the Cell-Surface and Intracellular Targets of Polyarginine-Conjugated Sodium Borocaptate as a Potential Delivery Agent for Boron Neutron Capture Therapy

Boron neutron capture therapy (BNCT) requires pharmaceutical innovations and molecular-based evidence of effectiveness to become a standard cancer therapeutic in the future. Recently, in Japan, 4-borono-L-phenylalanine (BPA) was approved as a boron agent for BNCT against head and neck (H&N) cancers. H&N cancer appears to be a suitable target for BPA-BNCT, because the expression levels of L-type amino acid transporter 1 (LAT1), one of the amino acid transporters responsible for BPA uptake, are elevated in most cases of H&N cancer. However, in other types of cancer including malignant brain tumors, LAT1 is not always highly expressed. To expand the possibility of BNCT for these cases, we previously developed poly-arginine peptide (polyR)-conjugated mercaptoundecahydrododecaborate (BSH). PolyR confers the cell membrane permeability and tumor selectivity of BSH. However, the molecular determinants for the properties are not fully understood. In this present study, we have identified the cluster of differentiation 44 (CD44) protein and translational machinery proteins as a major cell surface target and intracellular targets of BSH-polyR, respectively. CD44, also known as a stem cell-associated maker in various types of cancer, is required for the cellular uptake of polyR-conjugated molecules. We showed that BSH-polyR was predominantly delivered to a CD44(High) cell population of cancer cells. Once delivered, BSH-polyR interacted with the translational machinery components, including the initiation factors, termination factors, and poly(A)-biding protein (PABP). As a proof of principle, we performed BSH-polyR-based BNCT against glioma stem-like cells and revealed that BSH-polyR successfully induced BNCT-dependent cell death specifically in CD44(High) cells. Bioinformatics analysis indicated that BSH-polyR would be suitable for certain types of malignant tumors. Our results shed light on the biochemical properties of BSH-polyR, which may further contribute to the therapeutic optimization of BSH-BNCT in the future

The difficulty of eliminating donor leukocyte microchimerism in rat recipients bearing established organ allografts

Background. Unequivocal eradication of donor leukocyte microchimerism from recipients of long-surviving organ transplants has never been reported. Here we describe a drastic attempt to accomplish this objective. Methods. In control experiments, a rank order of microchimerism and of associated donor specific nonreactivity was produced in Brown-Norway (BN) rats by transplantation of Lewis (LEW) liver, bone marrow cell (BMC) and heart allografts under a brief course of tacrolimus. The degree of microchimerism at 60 and 110 days was estimated with semiquanitative immunocytochemical and PCR techniques. Tolerance at 110 days was assessed in the different control groups by challenge transplantation of naïve LEW hearts. In parallel experimental groups, an attempt was made to eliminate microchimerism from the BN recipients. The animals were submitted at 60 days to 9.5-Gy total body irradiation (TBI), reconstituted immediately with naïve BN BMC, and tested for donor specific nonreactivity by LEW heart transplantation at 110 days. Results. After the TBI-reconstitution at 60 days, microchimerism was undetectable in BMC recipients at 110 days, significantly reduced in heart recipients, and least affected in liver recipients. Except in liver recipients, abrogation of LEW-specific nonreactivity was demonstrated by rejection of the priming grafts, or by rejection of the challenge heart grafts, and by in vitro immune assay. Conclusions. It is difficult to eliminate microchimerism in organ recipients once the donor cells have settled into tissue niches. Copyright © 2006 by Lippincott Williams & Wilkins

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SHORT GRAIN1 Decreases Organ Elongation and Brassinosteroid Response in Rice1[W][OA]

We identified a short-grain mutant (Short grain1 (Sg1) Dominant) via phenotypic screening of 13,000 rice (Oryza sativa) activation-tagged lines. The causative gene, SG1, encodes a protein with unknown function that is preferentially expressed in roots and developing panicles. Overexpression of SG1 in rice produced a phenotype with short grains and dwarfing reminiscent of brassinosteroid (BR)-deficient mutants, with wide, dark-green, and erect leaves. However, the endogenous BR level in the SG1 overexpressor (SG1:OX) plants was comparable to the wild type. SG1:OX plants were insensitive to brassinolide in the lamina inclination assay. Therefore, SG1 appears to decrease responses to BRs. Despite shorter organs in the SG1:OX plants, their cell size was not decreased in the SG1:OX plants. Therefore, SG1 decreases organ elongation by decreasing cell proliferation. In contrast to the SG1:OX plants, RNA interference knockdown plants that down-regulated SG1 and a related gene, SG1-LIKE PROTEIN1, had longer grains and internodes in rachis branches than in the wild type. Taken together, these results suggest that SG1 decreases responses to BRs and elongation of organs such as seeds and the internodes of rachis branches through decreased cellular proliferation