An Asynchronous Federated Learning Aggregation Method Based on Adaptive Differential Privacy

Differential privacy is often used in location privacy protection because of its strict reasoning and proof privacy guarantee. When users make continuous location query, it will cause noise superposition, which leads to the decline of query accuracy. At present, although differential privacy based on rule tree structure can reduce the query error, it will generate a lot of invalid zero nodes. The data structure is too large, and more improvement in the query accuracy can be further investigated. In this paper, we proposed a differential privacy location privacy protection method based on generative adversary network. Firstly, the definition of location data privacy protection under differential privacy mechanism is given, and then resume density aware network under differential privacy mechanism. Based on density aware network, the privacy protection problem of location data can be transformed into the distribution of fitting trajectory length. Finally, we use Markov chain to generate a new trajectory, and introduce the generative adversarial network to construct a set differential privacy protection method. Compared with other methods to improve the accuracy of differential privacy query, this method can effectively reduce the problem of query accuracy decline caused by noise superposition in continuous query, and can adapt to lbs location query service in different density environments.KeywordsGenerative adversarial networkLocation differencePrivacy protectionMarkov chainDensity aware network

In response to the privacy leakage risks inherent in the big data processing of power user personas, propose a collaborative optimization‐based joint privacy protection mechanism for Differential Privacy (DP) and Secret Sharing (SS). This method reveals the inherent correlation between DP noise parameters and SS sharding strategy and designs an adaptive noise sharding mapping mechanism to achieve joint optimization of privacy protection and communication overhead. Based on this mechanism, a specific privacy protection scheme for power user personas is designed. Experimental results demonstrate that the DP + SS privacy protection method designed in this study achieves an accuracy rate of 93.14% on the MNIST dataset and maintains an accuracy rate of 92.06% across multiple datasets, indicating that the scheme effectively quantifies the level of privacy protection. The privacy protection level of the scheme is quantitatively defined through differential privacy budget ε ∈ [0.11,0.15], secret sharing ( k = 3, n = 5) threshold mechanism, and privacy leakage probability δ = 10 −5 . The privacy budget is dynamically allocated through the correlation between differential privacy noise variance and the minimum reconstruction threshold of secret sharing, ensuring that privacy risks are controllable and quantifiable. At the same time, the average training time for servers is about 186.4 s, which refers to the total end‐to‐end training time in a four‐server cluster environment. Compared with a single server encryption scheme, the efficiency is improved by 48.6%. The communication overhead has increased to 10.6GB, which is the total chip transmission overhead per 10,000 users. However, the calculation stability can be maintained through load balancing, indicating that the scheme has certain feasibility. The aforementioned research results not only provide a viable applied cryptographic technology solution for privacy protection in power big data but also offer new insights into balancing privacy protection strength and data availability. More importantly, the joint privacy protection mechanism proposed by the research institute can serve as a fundamental enabling technology for the infrastructure of a secure smart grid, providing quantifiable and trustworthy privacy and security guarantees for advanced data‐driven applications such as precise load prediction, demand‐side response, and collaborative optimization of distributed energy, thereby supporting the reliable and intelligent development of the smart grid.

Differential privacy (DP) is introduced into many fields of AI to preserve privacy. However, introducing DP into AI models is extremely error-prone. To verify whether DP AI models can provide privacy guarantee (quantified by privacy budget) as these models claim, existing methods utilize attack methods to audit whether privacy budget of these models is the same as these models claim. To further improve precision of privacy budget auditing, we propose a brand new way to audit privacy budget, namely directly utilizing the parameters of DP AI models to audit privacy budget. In particular, our method utilizes statistical characteristics variance of the output distribution of DP mechanism to audit privacy budget of DP mechanism. DP AI models are regarded as data samples from output distribution of DP AI model training method and are utilized to approximate the variance of output distribution. The approximated variance is leveraged to estimate the variance of noise distribution of DP mechanism and through the relationship between noise variance and privacy budget, our method calculates the audited privacy budget through estimated noise variance. In addition, to reduce computation overhead, our method constructs parameter selection strategy to identify position whose parameter is suitable for privacy budget auditing. Comprehensive experiments are conducted to verify the effectiveness of our auditing method. Comparison results of five competitive auditing methods demonstrate that our method decreases MAE by 18.29% and decreases MSE by 23.17% on experiment datasets.

OPTDP: Towards optimal personalized trajectory differential privacy for trajectory data publishing

Personal data privacy is a great concern by governments across the world as citizens generate huge amount of data continuously and industries using this for betterment of user centric services. There must be a reasonable balance between data privacy and utility of data. Differential privacy is a promise by data collector to the customer’s personal privacy. Centralised Differential Privacy (CDP) is performing output perturbation of user’s data by applying required privacy budget. This promises the inclusion or exclusion of individual’s data in data set not going to create significant change for a statistical query output and it offers -Differential privacy guarantee. CDP is holding a strong belief on trusted data collector and applying global sensitivity of the data. Local Differential Privacy (LDP) helps user to locally perturb his data and there by guaranteeing privacy even with untrusted data collector. Many differential privacy algorithms handles parameters like privacy budget, sensitivity and data utility in different ways and mostly trying to keep trade-off between privacy and utility of data. This paper evaluates differential privacy algorithms in regard to the privacy support it offers according to the sensitivity of the data. Generalized application of privacy budget is found ineffective in comparison to the sensitivity based usage of privacy budget.

Continuous publication of statistics collected from various location-based applications may compromise users’ privacy as the statistics could be procured from users’ private data. Differential Privacy (DP) is a new privacy notion that offers a strong privacy guarantee to all users who participate in the statistics. However, the existing DP mechanism for continuous publication of location statistics provides a privacy guarantee with the assumption that the data-points of users stream at consecutive timestamps are independent. In reality, users’ data-points may be temporally correlated, resulting in more privacy leakage due to an inadequate supply of privacy budget to the timestamps where the data-points are correlated. In this paper, we present a reformulated differential privacy definition to quantify the impact of temporal correlation on privacy leakage. Then, we introduce a privacy budget allocation method for allocating an adequate amount of privacy budget to each successive timestamps under the protection of differential privacy. Our solution adopts w-event privacy for continuously releasing statistics over infinite streams. The main idea is to check the dissimilarity between statistics at each timestamp and decide whether to publish current statistics or last release statistics. Finally, we evaluate the data utility of our proposed method by presenting experimental results for real and synthetic data sets.

Privacy budget management plays an important role when applying differential privacy, as it sets an upper limit in the ability to utilise the private database. In this paper, we explore the possibility of extending the total allocated privacy budget, taking into consideration the data consumer characteristics and the data utilisation context. To this end, we first study the problem of privacy budget distribution in adaptive multi-data consumer differential privacy use cases. Then, we present an extension of the classic differential privacy formal model that allows taking into consideration data consumers’ information disclosure risk when distributing the privacy budget among them. Finally, we define a method that allows to optimally distribute a given privacy budget among a private database’s data consumers.

Differential privacy can effectively help federated learning resist privacy attacks from various parties. However, existing approaches that use differential privacy for privacy protection greatly decrease the model performance of federated learning, especially in scenarios with complex model structures and large parameters. In this paper, we propose a novel privacy preservation scheme for federated learning that combines automatic gradient clipping and gradient transformation perturbation. Our approach primarily reduces the impact of differential privacy on federated learning from two aspects. Firstly, we efficiently control the gradient sensitivity by using automatic gradient clipping instead of traditional threshold clipping. Secondly, we utilize the space transformation technique to alleviate the dramatic accuracy degradation of the model caused by the insertion noise. Extensive experiments on various benchmark datasets demonstrate that our approach achieves a good trade-off between data privacy and effectiveness under the same privacy budget.

Differentially private graph neural networks for graph classification and its adaptive optimization

Face images, as an information carrier, are rich in sensitive information. Direct publication of these images would cause privacy leak, due to their natural weak privacy. Most of the existing privacy protection methods for face images adopt data publication under a non-interactive framework. However, the E-effect under this framework covers the entire image, such that the noise influence is uniform across the image. To solve the problem, this paper proposes region growing publication (RGP), an algorithm for the interactive publication of face images under differential privacy. This innovative algorithm combines the region growing technique with differential privacy technique. The privacy budget E is dynamically allocated, and the Laplace noise is added, according to the similarity between adjacent sub-images. To measure this similarity more effectively, the fusion similarity measurement mechanism (FSMM) was designed, which better adapts to the intrinsic attributes of images. Different from traditional region growing rules, the FSMM fully considers various attributes of images, including brightness, contrast, structure, color, texture, and spatial distribution. To further enhance algorithm feasibility, RGP was extended to atypical region growing publication (ARGP). While RGP limits the region growing direction between adjacent sub-images, ARGP searches for the qualified sub-images across the image, with the aid of the exponential mechanism, thereby expanding the region merging scope of the seed point. The results show that our algorithm can satisfy E-differential privacy, and the denoised image still have a high availability.

Convolutional neural networks (CNNs) are widely used in the field of image classification. At the same time, users face the risk of privacy leakage because adversaries can reverse private information from the training parameters of CNNs. Adding Gaussian noise to the training parameters is an effective means to prevent adversaries from stealing private, but this tends to reduce the utility of the models. Therefore, how to find a balance between privacy and utility has become a hot research topic. In this paper, to improve the image classification ability of CNN models under differential privacy protection, we propose an image classification algorithm based on layered gradient clipping under differential privacy, ICGC-DP for short. Firstly, the gradient tensor is layered according to the neural network model. Secondly, for each layered gradient tensor, the median of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${L_{2}}$ </tex-math></inline-formula> norms is used as the clipping threshold. Moreover, to prevent the sensitivity from converging to zero, we add a bound on the sensitivity to ensure that all gradients can be protected by differential privacy. To further improve the classification utility of ICGC-DP, we design an adaptive weighted fusion module for it. The module assigns weights to prediction tensors according to the variance between them. We conduct comprehensive experiments on the Mnist, FashionMnist and CIFAR10 datasets, respectively. The experimental results show that, when the privacy budget <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\varepsilon = 2.0$ </tex-math></inline-formula> , which indicates that the algorithm adds a large noise, ICGC-DP achieves 97.36%, 88.72% and 72.63% classification accuracy for the Minist, FasionMnist and CIFAR10 datasets, respectively; when the privacy budget <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\varepsilon = 8.0$ </tex-math></inline-formula> , which means the algorithm adds less noise, the classification accuracy of ICGC-DP for Minist, FasionMnist and CIFAR10 datasets reaches 97.81%, 89.49% and 74.41%, respectively.

Differential privacy in probabilistic systems

Decentralized IoT data sharing: A blockchain-based federated learning approach with joint optimizations for efficiency and privacy

In the differential privacy interactive framework, data sets need to be used to answer multiple queries. With the gradual consumption of the privacy budget, the risk of privacy disclosure increases. Therefore, it is essential to save and track the consumption of the privacy budget, which should not exceed the limit given by the privacy budget. Therefore, firstly, this paper optimizes the Gaussian mechanism to reduce the query response time; Then a Continuous Query Differential Privacy Mechanism (CQDPM) is designed to save the overhead of privacy budget and improve the availability of data; Use the blockchain to record the privacy budget to facilitate the query of the usage of the privacy budget; Finally, a data integrity verification algorithm is proposed by using blockchain. Experiments show that the proposed mechanism reduces the query response time, effectively saves the privacy budget overhead under the same privacy budget limit, and has higher data availability.KeywordsDifferential privacyGaussian mechanismBlockchain

A federated learning scheme meets dynamic differential privacy