k-anonymous Microdata Release via Post Randomisation Method

The problem of the release of anonymized microdata is an important topic in the fields of statistical disclosure control (SDC) and privacy preserving data publishing (PPDP), and yet it remains sufficiently unsolved. In these research fields, k-anonymity has been widely studied as an anonymity notion for mainly deterministic anonymization algorithms, and some probabilistic relaxations have been developed. However, they are not sufficient due to their limitations, i.e., being weaker than the original k-anonymity or requiring strong parametric assumptions. First we propose Pk-anonymity, a new probabilistic k-anonymity, and prove that Pk-anonymity is a mathematical extension of k-anonymity rather than a relaxation. Furthermore, Pk-anonymity requires no parametric assumptions. This property has a significant meaning in the viewpoint that it enables us to compare privacy levels of probabilistic microdata release algorithms with deterministic ones. Second, we apply Pk-anonymity to the post randomization method (PRAM), which is an SDC algorithm based on randomization. PRAM is proven to satisfy Pk-anonymity in a controlled way, i.e, one can control PRAM's parameter so that Pk-anonymity is satisfied. On the other hand, PRAM is also known to satisfy ${\varepsilon}$-differential privacy, a recent popular and strong privacy notion. This fact means that our results significantly enhance PRAM since it implies the satisfaction of both important notions: k-anonymity and ${\varepsilon}$-differential privacy.Comment: 22 pages, 4 figure

Determination of Low levels of Lead in Tap, River, Ground and Snow Waters using NH4H2PO4 and (NH4)2HPO4 modifiers with Tungsten-treated Pyrolytic Graphite Furnace Atomic Absorption Spectrometry

The W-treated pyrolytic graphite (PG) furnace made it possible to enhance the precision (RSD <2%), calculated limit of detection (LOD) and sensitivity of Pb by a 100 μL injection with 5 μL of modifier of 1w/v% NH4H2PO4 and 1w/v% (NH4)2HPO4. Using the phosphate modifier gave the LOD of 0.02 μg L-1 with a hollow cathode lamp as a radiation sauce. The modification effect on sulfate matrices, such as Na2SO4, K2SO4 and MgSO4 remaining a severe interference for a Pd modifier, was extended to be the upper limit to 50, 50 and 10 mg L-1 as cation concentration for each matrix, respectively. The recoveries of 1.00 μg L-1 of Pb added to tap, river and snow water samples were to be 104 ± 1 %, 105 ± 1 % and 102 ± 3 % with 1w/v% NH4H2PO4and to be 99±3 %, 99±2 % and 101±4 % with 1w/v% (NH4)2HPO4, respectively. The Pb concentration of Pb in a certified reference material of river water (MNIJ CRM 7202-a) was agreement with the certified value (1.01±0.02μg kg-1

Garbling Scheme for Formulas with Constant Size of Garbled Gates

We provide a garbling scheme which creates garbled circuits of a very small constant size (four bits per gate) for circuits with fan-out one (formulas). For arbitrary fan-out, we additionally need only two ciphertexts per additional connection of each gate output wire. We make use of a trapdoor permutation for which we define a generalized notion of correlation robustness. We show that our notion is implied by PRIV-security, a notion for deterministic (searchable) encryption. We prove our scheme secure in the programmable random oracle model

Actively Private and Correct MPC Scheme in t<n/2t < n/2 from Passively Secure Schemes with Small Overhead

Recently, several efforts to implement and use an unconditionally secure multi-party computation (MPC) scheme have been put into practice. These implementations are {\em passively} secure MPC schemes in which an adversary must follow the MPC schemes. Although passively secure MPC schemes are efficient, passive security has the strong restriction concerning the behavior of the adversary. We investigate how secure we can construct MPC schemes while maintaining comparable efficiency with the passive case, and propose a construction of an {\em actively} secure MPC scheme from passively secure ones. Our construction is secure in the $t < n/2$ setting, which is the same as the passively secure one. Our construction operates not only the theoretical minimal set for computing arbitrary circuits, that is, addition and multiplication, but also high-level operations such as shuffling and sorting. We do not use the broadcast channel in the construction. Therefore, privacy and correctness are achieved but {\em robustness} is absent; if the adversary cheats, a protocol may not be finished but anyone can detect the cheat (and may stop the protocol) without leaking secret information. Instead of this, our construction requires $O((c_B n + n^2)\kappa)$ communication that is comparable to one of the best known passively secure MPC schemes, $O((c_M n + n^2)\log n)$, where $\kappa$ denote the security parameter, $c_B$ denotes the sum of multiplication gates and high-level operations, and $c_M$ denotes the number of multiplication gates. Furthermore, we implemented our construction and confirmed that its efficiency is comparable to the current astest passively secure implementation

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

Further Case Studies of Human Infestation with Hard Tick (Acarina: Ixodidae) Found in Okayama, Japan

Six new cases of human infestation with hard tick (a 58-year-old man, a 85-year-old woman, a 54-year-old woman, a 74-year-old woman, a 68-year-old woman and a 76-year-old man) from Okayama Prefecture are further reported. The tick bites were found on the skin surface of left upper eyelid (Case 1), neck region (Cases 2 and 5), right abdomen (Case 3), left rump (Case 4) and left thorax (Case 6). On acarological observation, the removed ticks were identified as Ixodes ovatus Neumann, 1899 at nymphal stage (Case 1), the adult female of Haemaphysalis flava Neumann, 1897 (Case 2), Ixodes nipponensis Kitaoka and Saito, 1967 (Cases 3 and 6), H. flava (Case 4) and I. ovatus (Case 5) based on morphology of capitulum (hypostome and palps), internal and external spurs on coxae, spiracular plates and genital aperture. The tick bites have been occurred on hilly area (Cases 1 and 3), on farm garden (Case 2), and on grassy plain (Cases 5 and 6). The location of bite acquisition of Case 4 is not reported. To our best knowledge, the present report deals with 14th to 19th findings of human infestation with hard tick in Okayama Prefecture, Japan

Three-dimensional iodine mapping quantified by dual-energy CT for predicting programmed death-ligand 1 expression in invasive pulmonary adenocarcinoma

Yamagata K., Yanagawa M., Hata A., et al. Three-dimensional iodine mapping quantified by dual-energy CT for predicting programmed death-ligand 1 expression in invasive pulmonary adenocarcinoma. Scientific Reports 14, 18310 (2024); https://doi.org/10.1038/s41598-024-69470-9.We examined the association between texture features using three-dimensional (3D) io-dine density histogram on delayed phase of dual-energy CT (DECT) and expression of programmed death-ligand 1 (PD-L1) using immunostaining methods in non-small cell lung cancer. Consecutive 37 patients were scanned by DECT. Unenhanced and enhanced (3 min delay) images were obtained. 3D texture analysis was performed for each nodule to obtain 7 features (max, min, median, mean, standard deviation, skewness, and kurtosis) from iodine density mapping and extracellular volume (ECV). A pathologist evaluated a tumor proportion score (TPS, %) using PD-L1 immunostaining: PD-L1 high (TPS ≥ 50%) and low or negative expression (TPS < 50%). Associations between PD-L1 expression and each 8 parameter were evaluated using logistic regression analysis. The multivariate logistic regression analysis revealed that skewness and ECV were independent indicators associated with high PD-L1 expression (skewness: odds ratio [OR] 7.1 [95% CI 1.1, 45.6], p = 0.039; ECV: OR 6.6 [95% CI 1.1, 38.4], p = 0.037). In the receiver-operating characteristic analysis, the area under the curve of the combination of skewness and ECV was 0.83 (95% CI 0.67, 0.93) with sensitivity of 64% and specificity of 96%. Skewness from 3D iodine density histogram and ECV on dual energy CT were significant factors for predicting PD-L1 expression

An Efficient Secure Three-Party Sorting Protocol with an Honest Majority

We present a novel three-party sorting protocol secure against passive adversaries in the honest majority setting. The protocol can be easily combined with other secure protocols which work on shared data, and thus enable different data analysis tasks, such as data deduplication, set intersection, and computing percentiles. The new sorting protocol is based on radix sort. It is asymptotically better compared to previous sorting protocols since it does not need to shuffle the entire length of the items after each comparison step. We further improve the concrete efficiency by using not only optimizations but also novel protocols, which are independent of interest. We implemented our sorting protocol with those optimizations and protocols. Our experiments show that our implementation is concretely fast. For example, sorting one million $20$-bit items takes 4.6 seconds in 1G connection. It enables a new set of applications on large-scale datasets since the known implementations handle thousands of items about 10 seconds