Client Storage Research Articles

Entangled cloud storage

Entangled cloud storage (Aspnes et al., ESORICS 2004) enables a set of clients to “entangle” their files into a single clew to be stored by a (potentially malicious) cloud provider. The entanglement makes it impossible to modify or delete significant part of the clew without affecting all files encoded in the clew. A clew keeps the files in it private but still lets each client recover his own data by interacting with the cloud provider; no cooperation from other clients is needed. At the same time, the cloud provider is discouraged from altering or overwriting any significant part of the clew as this will imply that none of the clients can recover their files.We put forward the first simulation-based security definition for entangled cloud storage, in the framework of universal composability (Canetti, 2001). We then construct a protocol satisfying our security definition, relying on an entangled encoding scheme based on privacy-preserving polynomial interpolation; entangled encodings were originally proposed by Aspnes et al. as useful tools for the purpose of data entanglement. As a contribution of independent interest we revisit the security notions for entangled encodings, putting forward stronger definitions than previous work (that for instance did not consider collusion between clients and the cloud provider).Protocols for entangled cloud storage find application in the cloud setting, where clients store their files on a remote server and need to be ensured that the cloud provider will not modify or delete their data illegitimately. Current solutions, e.g., based on Provable Data Possession and Proof of Retrievability, require the server to be challenged regularly to provide evidence that the clients’ files are stored at a given time. Entangled cloud storage provides an alternative approach where any single client operates implicitly on behalf of all others, i.e., as long as one client’s files are intact, the entire remote database continues to be safe and unblemished.

Implementation of a deduplication cache mechanism using content-defined chunking

Many application programs in data-intensive science read and write large files. Large data consume significant memory because the data is loaded into the page cache. Since memory resources are critically valuable in data-intensive computing, reducing the memory footprint consumed by file data is essential. In this paper, we propose a cache deduplication mechanism with content-defined chunking CDC for the Gfarm distributed file system. CDC divides a file into variable-size blocks chunks based on the contents of the file. The client stores the chunks in the local file system as cache files and reuses them during subsequent file accesses. Deduplication of chunks reduces the amount of transmitted data between clients and servers, and reduces storage and memory requirements. The experimental results demonstrate that the proposed mechanism significantly improves the performance of file-read operations and that the introduction of parallelism reduces the overhead of file-write operations.

속성 기반 암호화 방식을 이용한 다중 서버 패스워드 인증 키 교환

Password authenticated key exchange (PAKE) is a protocol that a client stores its password to a server, authenticates itself using its password and shares a session ke y with the server. In multi-server PAKE, a client splits its password and stores them to several servers separately. Unless all the servers are compromised, client's password will not be disclosed in the multi-server setting. In attribute-based encryption (ABE), a sender encrypts a message M using a set of attributes and then a receiver decrypts it using the same set of attributes. In this paper, we introduce multi-server PAKE protocol that utilizes a set of attributes of ABE as a client's password. In the protocol, the client and servers do not need to create additional public/private key pairs because the password is used as a set of public keys. Also, the client and the servers exchange only one round-trip message per server. The protocol is secure against dictionary attacks. We prove our system is secure in a proposed threat model. Finally we show feasibility through evaluating the execution time of the protocol.

Dynamic proofs of retrievability with square-root oblivious RAM

With the development of cloud storage, the problem of security, such as efficiently checking and proving data integrity needs more consideration. Therefore, much of growing interest has been pursed in the context of the integrity verification of cloud storage. Provable data possession (PDP) and proofs of retrievability (POR) are two kinds of important scheme which can guarantee the data integrity in the cloud storage environments. The main difference between them is that POR schemes store a redundant encoding of the client data on the server so as to she has the ability of retrievability while PDP does not have. Unfortunately most of POR schemes support only static data. Stefanov et al. proposed a dynamic POR, but their scheme need a large of amount of client storage and has a large audit cost. Cash et al. use Oblivious RAM (ORAM) to construct a fully dynamic POR scheme, but the cost of their scheme is also very heavy. Based on the idea which proposed by Cash, we propose dynamic POR via Square-Root Oblivious RAM (The complexity of the Oblivious RAM is square-root, therefore we call it Square-Root Oblivious RAM). In this paper we call our scheme DPOR–SRORAM for short. Firstly, the notions which are used in our scheme are defined. The Square-Root ORAM (SORAM) protocol is also proposed. The DPOR–SRORAM Model which includes the formal definitions, security definitions and model construction methods are described in the paper. Finally, we give the security analysis and efficiency analysis. The analysis results show that our scheme not only has the property of correctness, authenticity, next-read pattern hiding and retrievability, but also has the high efficiency.

Authenticated Hash Tables Based on Cryptographic Accumulators

Suppose a client stores \(n\) elements in a hash table that is outsourced to an untrusted server. We address the problem of authenticating the hash table operations, where the goal is to design protocols capable of verifying the correctness of queries and updates performed by the server, thus ensuring the integrity of the remotely stored data across its entire update history. Solutions to this authentication problem allow the client to gain trust in the operations performed by a faulty or even malicious server that lies outside the administrative control of the client. We present two novel schemes that implement an authenticated hash table. An authenticated hash table exports the basic hash-table functionality for maintaining a dynamic set of elements, coupled with the ability to provide short cryptographic proofs that a given element is a member or not of the current set. By employing efficient algorithmic constructs and cryptographic accumulators as the core security primitive, our schemes provide constant proof size, constant verification time and sublinear query or update time, strictly improving upon previous approaches. Specifically, in our first scheme which is based on the RSA accumulator, the server is able to construct a (non-)membership proof in constant time and perform updates in \(O\left( n^{\epsilon }\log n\right) \) time for any fixed constant \(0<\epsilon <1\). A variation of this scheme achieves a different trade-off, offering constant update time and \(O(n^{\epsilon })\) query time. Our second scheme uses an accumulator based on bilinear pairings to achieve \(O(n^{\epsilon })\) update time at the server while keeping all other complexities constant. A variation of this scheme achieves \(O(n^{\epsilon }\log n)\) time for queries and constant update time. An experimental evaluation of both solutions shows their practicality.

The Implementation of Cloud Storage System Based on OpenStack Swift

This paper describes the implementation of a fast and efficient method to build a cloud storage environment. In this method, we base on the OpenStack Object Storage (code-named swift), use Swauth as the authentication system, and build a S3-compatible cloud storage platform. Then do a second development of open source software Cyberduck and use it as the cloud storage Client.

클라우드 컴퓨팅을 이용한 유시티 비디오 빅데이터 분석

유비쿼터스 시티(유시티)에서는 수많은 비디오 카메라들이 설치된다. 이렇게 설치된 많은 카메라로부터 대용량의 비디오 데이터가 실시간으로 끊임없이 발생하고 유시티의 관리 시스템으로 전달된다. 유시티의 다양한 서비스들을 뒷받침하기 위해서는 이러한 비디오 데이터를 저장하고, 이렇게 저장된 대용량의 비디오 데이터를 분석할 수 있는 방법과 관리 시스템이 요구된다. 그래서, 이 논문에서는 클라우드 컴퓨팅을 기반으로 한 유시티 비디오 관리 시스템을 제안한다. 또한, 근래 주목받고 있는 데이터 병렬처리 프레임워크인 Hadoop MapReduce를 이용하여 이러한 빅데이터 비디오를 분석하는 방법을 제안하고, 이에 따른 우리의 성능 평가를 소개한다. The Ubiquitous-City (U-City) is a smart or intelligent city to satisfy human beings' desire to enjoy IT services with any device, anytime, anywhere. It is a future city model based on Internet of everything or things (IoE or IoT). It includes a lot of video cameras which are networked together. The networked video cameras support a lot of U-City services as one of the main input data together with sensors. They generate huge amount of video information, real big data for the U-City all the time. It is usually required that the U-City manipulates the big data in real-time. And it is not easy at all. Also, many times, it is required that the accumulated video data are analyzed to detect an event or find a figure among them. It requires a lot of computational power and usually takes a lot of time. Currently we can find researches which try to reduce the processing time of the big video data. Cloud computing can be a good solution to address this matter. There are many cloud computing methodologies which can be used to address the matter. MapReduce is an interesting and attractive methodology for it. It has many advantages and is getting popularity in many areas. Video cameras evolve day by day so that the resolution improves sharply. It leads to the exponential growth of the produced data by the networked video cameras. We are coping with real big data when we have to deal with video image data which are produced by the good quality video cameras. A video surveillance system was not useful until we find the cloud computing. But it is now being widely spread in U-Cities since we find some useful methodologies. Video data are unstructured data thus it is not easy to find a good research result of analyzing the data with MapReduce. This paper presents an analyzing system for the video surveillance system, which is a cloud-computing based video data management system. It is easy to deploy, flexible and reliable. It consists of the video manager, the video monitors, the storage for the video images, the storage client and streaming IN component. The "video monitor" for the video images consists of "video translater" and "protocol manager". The "storage" contains MapReduce analyzer. All components were designed according to the functional requirement of video surveillance system. The "streaming IN" component receives the video data from the networked video cameras and delivers them to the "storage client". It also manages the bottleneck of the network to smooth the data stream. The "storage client" receives the video data from the "streaming IN" component and stores them to the storage. It also helps other components to access the storage. The "video monitor" component transfers the video data by smoothly streaming and manages the protocol. The "video translator" sub-component enables users to manage the resolution, the codec and the frame rate of the video image. The "protocol" sub-component manages the Real Time Streaming Protocol (RTSP) and Real Time Messaging Protocol (RTMP). We use Hadoop Distributed File System(HDFS) for the storage of cloud computing. Hadoop stores the data in HDFS and provides the platform that can process data with simple MapReduce programming model. We suggest our own methodology to analyze the video images using MapReduce in this paper. That is, the workflow of video analysis is presented and detailed explanation is given in this paper. The performance evaluation was experiment and we found that our proposed system worked well. The performance evaluation results are presented in this paper with analysis. With our cluster system, we used compressed <TEX>$1920{\times}1080(FHD)$</TEX> resolution video data, H.264 codec and HDFS as video storage. We measured the processing time according to the number of frame per mapper. Tracing the optimal splitting size of input data and the processing time according to the number of node, we found the linearity of the system performance.

An Enhanced Remote Data Checking Scheme for Dynamic Updates

A client stores data in the cloud and uses remote data checking (RDC) schemes to check the integrity of the data. The client can detect the corruption of the data using RDC schemes. Recently, robust RDC schemes have integrated forward error-correcting codes (FECs) to ensure the integrity of data while enabling dynamic update operations. Thus, minor data corruption can be recovered by FECs, whereas major data corruption can be detected by spot-checking techniques. However, this requires high communication overhead for dynamic update, because a small update may require the client to download an entire file. The Variable Length Constraint Group (VLCG) scheme overcomes this disadvantage by downloading the RS-encoded parity data for update instead of the entire file. Despite this, it needs to download all the parity data for any minor update. In this paper, we propose an improved RDC scheme in which the communication overhead can be reduced by downloading only a part of the parity data for update while simultaneously ensuring the integrity of the data. Efficiency and security analysis show that the proposed scheme enhances efficiency without any security degradation.

TransCom: A Virtual Disk-Based Cloud Computing Platform for Heterogeneous Services

This paper presents the design, implementation, and evaluation of TransCom, a virtual disk (Vdisk) based cloud computing platform that supports heterogeneous services of operating systems (OSes) and their applications in enterprise environments. In TransCom, clients store all data and software, including OS and application software, on Vdisks that correspond to disk images located on centralized servers, while computing tasks are carried out by the clients. Users can choose to boot any client for using the desired OS, including Windows, and access software and data services from Vdisks as usual without consideration of any other tasks, such as installation, maintenance, and management. By centralizing storage yet distributing computing tasks, TransCom can greatly reduce the potential system maintenance and management costs. We have implemented a multi-platform TransCom prototype that supports both Windows and Linux services. The extensive evaluation based on both test-bed experiments and real-usage experiments has demonstrated that TransCom is a feasible, scalable, and efficient solution for successful real-world use.

Research on Offline Storage of Web Page

Offline storage technology has many uses in the Web application and it can store the user status, cache data, temporary data, and persistent data and so on. In this paper several typical web client storage technologies are discussed and it includes the IE browser's unique storage technology UserData, localStorage and sessionStorage of HTML5, Web SQL Databases, Indexed Database, as well as classic storage technology Cookie and so on. Their concrete using methods are explained and their individual strengths and differences are compared. Their respective applications occasions and some issues that need attention are discussed. The general cross-browser offline storage method is presented and it can use the same application programming interface to complete different browser offline storage technologies.

Access privacy and correctness on untrusted storage

We introduce a new practical mechanism for remote data storage with access pattern privacy and correctness . A storage client can deploy this mechanism to issue encrypted reads, writes, and inserts to a potentially curious and malicious storage service provider, without revealing information or access patterns. The provider is unable to establish any correlation between successive accesses, or even to distinguish between a read and a write. Moreover, the client is provided with strong correctness assurances for its operations—illicit provider behavior does not go undetected. We describe a practical system that can execute an unprecedented several queries per second on terabyte-plus databases while maintaining full computational privacy and correctness.

The Nonvolatile Memory Transformation of Client Storage

The introduction of solid-state drives in mainstream computing systems is reshaping the client storage landscape. PCI Express is supplanting Serial ATA to deliver higher performance, while novel caching solutions are extending the benefits of nonvolatile memory to a wider segment of users at a more affordable price.

Data Integrity Check and Repair in Design and Manufacture of Distributed Storage Network

When clients store large files on a remote network of unreliable distributed servers, they want to verify that their files are properly stored in the servers without any modification. This can be achieved by the techniques of data integrity. In this paper, we consider how to implement data integrity check by a third party auditor (TPA) in a distributed storage network, with the help of BLS signature. We also consider how the distributed storage network restores data when some server fails or some server crushes down. We present a data integrity check and repair (DICR) scheme, which makes use of a random linear code for data restoration and BLS signature to implement data integrity check. Our scheme is robust in the way that the storage network can reconstruct the data when a limited number of servers fail. In the mean time, public auditing on the storage network liberates clients from computational overhead.

Storage Aggregation over a Network

The most valuable asset of any organization is data. Should this data be lost, it can be a potential threat to any business. Any enterprise/ company cannot afford such business interruptions. Such companies normally use the client server model to store their data. In the client-server model, all the data is stored on a server and the clients access it. This system has its own disadvantages. The fundamental one being that the space on the client machines is not utilized to the fullest. In order to overcome this limitation, we propose a model in which server utilizes the available space on the client machines which can be used for backup. Thus we describe a novel method which stores the data on the clients rather than on the server. Hence the cost, risk of losing the data and dependency on the server is reduced as well as the client storage space is fully utilized. Thus optimum usage of storage space on the clients to improve the efficiency and reliability of data storage on the network is the main aim of the project.

Short Communication: A Support Mount Made from Nomex Card For Storage and Three-dimensional Display Of an Incomplete and Fragile 19th-century Straw Bonnet

The aim of this project was to prepare a fragile and incomplete 19th-century straw bonnet for storage and occasional display. When brought for conservation the bonnet exhibited a distorted and shallow shape due to the loss of the crown and previous repairs, the straw was brittle, and the wire was distorted but flexible. The mount solution addressed the problem that arose from the conflicting demand for the bonnet to be stored flat because of the client's storage constraints, while retaining the ability to display the bonnet in a three-dimensional shape. This article discusses the condition of the object before treatment, the treatment undertaken, the method of making the mount from Nomex 410 card (meta-aramid), the functionality of the mount for flat storage, and its assembly for three-dimensional display. The support mount reconstructed the bonnet's original shape and compensated for the missing areas. It enabled the client to store the bonnet flat and to arrange the bonnet safely into shape. The mount eliminated the need to handle the bonnet excessively when arranging it for display.

Zero Data Remnance Proof in Cloud Storage

In a cloud environment where Storage is offered as a service, a client stores his data with a provider and pays as per the usage. Once the contract ends, the client, as the data owner, may like to see, due to privacy reasons and otherwise that the data is properly shredded in the provider storage. In this paper we propose a scheme for Zero Data Remnance Proof (ZDRP) – a comprehensive proof given by the cloud data storage provider as regards to zero data remnance post the SLA period. In absence of such shredding the provider can consume the data to his benefit without coming in legal framework. The proof of data destruction can be achieved together by clauses in the SLA and a comprehensive destruction-verifier algorithm. The implementation of this can be achieved by appropriate modification of the data updation mechanisms provided by open source cloud providers.

Document Management and Exchange System – Supporting Education Process

Development and implementation of new technologies are very important in education. One of the most challenging tasks in the education process is to build efficient and cost-friendly system for content management and exchange. The system has to be reliable, easy manageable and open. Centralized storage, secured access, and ubiquitous client technologies have emerged as best-practice solutions in engineering that kind of services. Users can easily publish or exchange documents and not need to worry about their distribution, storage or technical skills required for efficient document management. The system that will be presented is built on open source technologies and is deployable on all today's popular web software platforms. The web server, the programming language and operating system that are used to build and deploy such a system are all non-proprietary and completely open because our mission was to build system that can be easily extended and not limited by its corporate license. The system uses security mechanisms such as user group access policy, operating system level security (file system) and secured data storage in database.&#x0D; Because of the growing need for document management in education process we believe that this project will find its place in practice.

GUEST EDITORIAL From the MIPRO CE 2009 Conference Publication Chair

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Alternate video broadcasting scheme for popular videos

A video segment broadcasting scheme can reduce server and network bandwidth by periodically broadcasting popular videos that are most likely demanded by clients, instead of responding to each client requests. When video segments broadcast on a channel, in general, alternate broadcasting schemes periodically transmit all segments on a given channel with the same transmission period, which reduces the transmission efficiency of stream channels and requires sufficient client storage space for video segments broadcast on simultaneous channels. The author proposed a novel alternate video broadcast scheme, a delayed buffering broadcast that requires lower server bandwidth and client buffer space compared with those of previous approaches. In addition, the study provides an analytical analysis of the scheme, including a lower bound on the video segment transmission rate for any alternate broadcast scheme. It also derives an upper bound on its storage requirements from the client side. Using the performance study of the proposed scheme and simulation results, the author establishes that the proposed scheme uses fewer server channels and storage resources than previously reported alternate video broadcast schemes for any given client waiting time.

Query processing methods considering the deadline of queries for database broadcasting systems

AbstractIn recent years, there has been an increasing interest in the database broadcasting system where the server periodically broadcasts contents of a database to mobile clients such as portable computers and PDAs. There are three query processing methods in the database broadcasting system: (i) the server processes a query and then broadcasts the query result to the client, (ii) the client stores all data that are necessary to process the query and then processes it locally, and (iii) the server and the client collaborate in processing the query. Since the performance of each method changes according to the situation such as the interval of query generation and the size of query results, it is difficult to choose the optimal method among them statically. In this paper, we propose new query processing methods which dynamically change the order of queries submitted in the queue at the server and also change processing methods for the queries according to the deadline of queries and the system situation. These methods improve the success rate as well as reduce the response time in most cases. © 2007 Wiley Periodicals, Inc. Syst Comp Jpn, 38(2): 21– 31, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.20689