194 research outputs found
Public-Key Encryption with Delegated Search
In public-key setting, Alice encrypts email with public key of Bob, so that only Bob will be able to learn contents of email. Consider scenario when computer of Alice is infected and unbeknown to Alice it also embeds malware into message. Bob's company, Carol, cannot scan his email for malicious content as it is encrypted so burden is on Bob to do scan. This is not efficient. We construct mechanism that enables Bob to provide trapdoors to Carol such that Carol, given encrypted data and malware signature, is able to check whether encrypted data contains malware signature, without decrypting it. We refer to this mechanism as Public-Key Encryption with Delegated Search SPKE.\ud
\ud
We formalize SPKE and give construction based on ElGamal public-key encryption (PKE). proposed scheme has ciphertexts which are both searchable and decryptable. This property of scheme is crucial since entity can search entire content of message, in contrast to existing searchable public-key encryption schemes where search is done only in metadata part. We prove in standard model that scheme is ciphertext indistinguishable and trapdoor indistinguishable under Symmetric External Diffie-Hellman (sxdh) assumption. We prove also ciphertext one-wayness of scheme under modified Computational Diffie-Hellman (mcdh) assumption. We show that our PKEDS scheme can be used in different applications such as detecting encrypted malwares and forwarding encrypted emails
Efficient Strong Privacy-Preserving Conjunctive Keyword Search Over Encrypted Cloud Data
Searchable symmetric encryption (SSE) supports keyword search over outsourced
symmetrically encrypted data. Dynamic searchable symmetric encryption (DSSE), a
variant of SSE, further enables data updating. Most DSSE works with conjunctive
keyword search primarily consider forward and backward privacy. Ideally, the
server should only learn the result sets involving all keywords in the
conjunction. However, existing schemes suffer from keyword pair result pattern
(KPRP) leakage, revealing the partial result sets containing two of query
keywords. We propose the first DSSE scheme to address aforementioned concerns
that achieves strong privacy-preserving conjunctive keyword search.
Specifically, our scheme can maintain forward and backward privacy and
eliminate KPRP leakage, offering a higher level of security. The search
complexity scales with the number of documents stored in the database in
several existing schemes. However, the complexity of our scheme scales with the
update frequency of the least frequent keyword in the conjunction, which is
much smaller than the size of the entire database. Besides, we devise a least
frequent keyword acquisition protocol to reduce frequent interactions between
clients. Finally, we analyze the security of our scheme and evaluate its
performance theoretically and experimentally. The results show that our scheme
has strong privacy preservation and efficiency
FSPVDsse: A Forward Secure Publicly Verifiable Dynamic SSE scheme
A symmetric searchable encryption (SSE) scheme allows a client (data owner)
to search on encrypted data outsourced to an untrusted cloud server. The search
may either be a single keyword search or a complex query search like
conjunctive or Boolean keyword search. Information leakage is quite high for
dynamic SSE, where data might be updated. It has been proven that to avoid this
information leakage an SSE scheme with dynamic data must be forward private. A
dynamic SSE scheme is said to be forward private, if adding a keyword-document
pair does not reveal any information about the previous search result with that
keyword.
In SSE setting, the data owner has very low computation and storage power. In
this setting, though some schemes achieve forward privacy with
honest-but-curious cloud, it becomes difficult to achieve forward privacy when
the server is malicious, meaning that it can alter the data. Verifiable dynamic
SSE requires the server to give a proof of the result of the search query. The
data owner can verify this proof efficiently. In this paper, we have proposed a
generic publicly verifiable dynamic SSE (DSSE) scheme that makes any forward
private DSSE scheme verifiable without losing forward privacy. The proposed
scheme does not require any extra storage at owner-side and requires minimal
computational cost as well for the owner. Moreover, we have compared our scheme
with the existing results and show that our scheme is practical.Comment: 17 pages, Published in ProvSec 201
Practical Architectures for Deployment of Searchable Encryption in a Cloud Environment
Public cloud service providers provide an infrastructure that gives businesses and individuals access to computing power and storage space on a pay-as-you-go basis. This allows these entities to bypass the usual costs associated with having their own data centre such as: hardware, construction, air conditioning and security costs, for example, making this a cost-effective solution for data storage. If the data being stored is of a sensitive nature, encrypting it prior to outsourcing it to a public cloud is a good method of ensuring the confidentiality of the data. With the data being encrypted, however, searching over it becomes unfeasible. In this paper, we examine different architectures for supporting search over encrypted data and discuss some of the challenges that need to be overcome if these techniques are to be engineered into practical systems
Secure Remote Storage of Logs with Search Capabilities
Dissertação de Mestrado em Engenharia InformáticaAlong side with the use of cloud-based services, infrastructure and storage, the use of application logs
in business critical applications is a standard practice nowadays. Such application logs must be stored
in an accessible manner in order to used whenever needed. The debugging of these applications is a
common situation where such access is required. Frequently, part of the information contained in logs
records is sensitive.
This work proposes a new approach of storing critical logs in a cloud-based storage recurring to
searchable encryption, inverted indexing and hash chaining techniques to achieve, in a unified way, the
needed privacy, integrity and authenticity while maintaining server side searching capabilities by the logs
owner.
The designed search algorithm enables conjunctive keywords queries plus a fine-grained search
supported by field searching and nested queries, which are essential in the referred use case. To the
best of our knowledge, the proposed solution is also the first to introduce a query language that enables
complex conjunctive keywords and a fine-grained search backed by field searching and sub queries.A gerac¸ ˜ao de logs em aplicac¸ ˜oes e a sua posterior consulta s˜ao fulcrais para o funcionamento de qualquer
neg´ocio ou empresa. Estes logs podem ser usados para eventuais ac¸ ˜oes de auditoria, uma vez
que estabelecem uma baseline das operac¸ ˜oes realizadas. Servem igualmente o prop´ osito de identificar
erros, facilitar ac¸ ˜oes de debugging e diagnosticar bottlennecks de performance. Tipicamente, a maioria
da informac¸ ˜ao contida nesses logs ´e considerada sens´ıvel.
Quando estes logs s˜ao armazenados in-house, as considerac¸ ˜oes relacionadas com anonimizac¸ ˜ao,
confidencialidade e integridade sËśao geralmente descartadas. Contudo, com o advento das plataformas
cloud e a transic¸ ˜ao quer das aplicac¸ ˜oes quer dos seus logs para estes ecossistemas, processos de
logging remotos, seguros e confidenciais surgem como um novo desafio. Adicionalmente, regulac¸ ˜ao
como a RGPD, imp˜oe que as instituic¸ ˜oes e empresas garantam o armazenamento seguro dos dados.
A forma mais comum de garantir a confidencialidade consiste na utilizac¸ ˜ao de t ´ecnicas criptogr ´aficas
para cifrar a totalidade dos dados anteriormente `a sua transfer ˆencia para o servidor remoto. Caso sejam
necess´ arias capacidades de pesquisa, a abordagem mais simples ´e a transfer ˆencia de todos os dados
cifrados para o lado do cliente, que proceder´a `a sua decifra e pesquisa sobre os dados decifrados.
Embora esta abordagem garanta a confidencialidade e privacidade dos dados, rapidamente se torna
impratic ´avel com o crescimento normal dos registos de log. Adicionalmente, esta abordagem n˜ao faz
uso do potencial total que a cloud tem para oferecer.
Com base nesta tem´ atica, esta tese prop˜oe o desenvolvimento de uma soluc¸ ˜ao de armazenamento
de logs operacionais de forma confidencial, integra e autˆ entica, fazendo uso das capacidades de armazenamento
e computac¸ ˜ao das plataformas cloud. Adicionalmente, a possibilidade de pesquisa sobre
os dados ´e mantida. Essa pesquisa ´e realizada server-side diretamente sobre os dados cifrados e sem
acesso em momento algum a dados nËśao cifrados por parte do servidor..
A Practical Framework for Storing and Searching Encrypted Data on Cloud Storage
Security has become a significant concern with the increased popularity of
cloud storage services. It comes with the vulnerability of being accessed by
third parties. Security is one of the major hurdles in the cloud server for the
user when the user data that reside in local storage is outsourced to the
cloud. It has given rise to security concerns involved in data confidentiality
even after the deletion of data from cloud storage. Though, it raises a serious
problem when the encrypted data needs to be shared with more people than the
data owner initially designated. However, searching on encrypted data is a
fundamental issue in cloud storage. The method of searching over encrypted data
represents a significant challenge in the cloud.
Searchable encryption allows a cloud server to conduct a search over
encrypted data on behalf of the data users without learning the underlying
plaintexts. While many academic SE schemes show provable security, they usually
expose some query information, making them less practical, weak in usability,
and challenging to deploy. Also, sharing encrypted data with other authorized
users must provide each document's secret key. However, this way has many
limitations due to the difficulty of key management and distribution.
We have designed the system using the existing cryptographic approaches,
ensuring the search on encrypted data over the cloud. The primary focus of our
proposed model is to ensure user privacy and security through a less
computationally intensive, user-friendly system with a trusted third party
entity. To demonstrate our proposed model, we have implemented a web
application called CryptoSearch as an overlay system on top of a well-known
cloud storage domain. It exhibits secure search on encrypted data with no
compromise to the user-friendliness and the scheme's functional performance in
real-world applications.Comment: 146 Pages, Master's Thesis, 6 Chapters, 96 Figures, 11 Table
GraphSE: An Encrypted Graph Database for Privacy-Preserving Social Search
In this paper, we propose GraphSE, an encrypted graph database for online
social network services to address massive data breaches. GraphSE preserves
the functionality of social search, a key enabler for quality social network
services, where social search queries are conducted on a large-scale social
graph and meanwhile perform set and computational operations on user-generated
contents. To enable efficient privacy-preserving social search, GraphSE
provides an encrypted structural data model to facilitate parallel and
encrypted graph data access. It is also designed to decompose complex social
search queries into atomic operations and realise them via interchangeable
protocols in a fast and scalable manner. We build GraphSE with various
queries supported in the Facebook graph search engine and implement a
full-fledged prototype. Extensive evaluations on Azure Cloud demonstrate that
GraphSE is practical for querying a social graph with a million of users.Comment: This is the full version of our AsiaCCS paper "GraphSE: An
Encrypted Graph Database for Privacy-Preserving Social Search". It includes
the security proof of the proposed scheme. If you want to cite our work,
please cite the conference version of i
An In-Depth Analysis on Efficiency and Vulnerabilities on a Cloud-Based Searchable Symmetric Encryption Solution
Searchable Symmetric Encryption (SSE) has come to be as an integral cryptographic approach in a world where digital privacy is essential. The capacity to search through encrypted data whilst maintaining its integrity meets the most important demand for security and confidentiality in a society that is increasingly dependent on cloud-based services and data storage. SSE offers efficient processing of queries over encrypted datasets, allowing entities to comply with data privacy rules while preserving database usability. Our research goes into this need, concentrating on the development and thorough testing of an SSE system based on Curtmola’s architecture and employing Advanced Encryption Standard (AES) in Cypher Block Chaining (CBC) mode. A primary goal of the research is to conduct a thorough evaluation of the security and performance of the system. In order to assess search performance, a variety of database settings were extensively tested, and the system's security was tested by simulating intricate threat scenarios such as count attacks and leakage abuse. The efficiency of operation and cryptographic robustness of the SSE system are critically examined by these reviews
A SURVEY ON KEY-AGGREGATE SEARCHABLE ENCRYPTION FOR GROUP DATA SHARING IN CLOUD STORAGE
Security concerns over inadvertent data leaks in the cloud may greatly ease the capability of selectively sharing encrypted data with different users via public cloud storage. So designing such an encryption schemes is a key challenge which lies in the efficient management of encryption keys. When any group of selected documents need to share with any group of users a desired flexibility is required with demands different encryption keys, which are used for different documents. However this also indicates the need of securely sharing to users a large number of keys for encryption and search, and those users will have to safely save the received keys, and submit an equally large number of keywords trapdoors to the cloud in order to perform search over the shared data. The indicated purpose of safe communication, storage, and difficultly clearly renders the approach impractical. In this paper, we address this practical problem, which is greatly neglected in the literature, here we are proposing the new concept of key aggregate searchable encryption and instantiating the concept through a concrete KASE scheme. In this scheme, the documents are shared by just submitting a single trapdoor by the user to the cloud for querying and this single key is being received by the data owner for sharing large number of documents. Our proposed scheme can confirm prove both the safety as well as practically efficient channels by security analysis and performance evaluation. It can securely store and manage the users in their devices. In order to perform a keyword search over many files a large number of trapdoors must be generated by users and submitted to the cloud. Such a system with secure communication, storage and computational complexity may lead to inefficiency and impracticality
- …