CryptDB: A Practical Encrypted Relational DBMS

CryptDB is a DBMS that provides provable and practical privacy in the face of a compromised database server or curious database administrators. CryptDB works by executing SQL queries over encrypted data. At its core are three novel ideas: an SQL-aware encryption strategy that maps SQL operations to encryption schemes, adjustable query-based encryption which allows CryptDB to adjust the encryption level of each data item based on user queries, and onion encryption to efficiently change data encryption levels. CryptDB only empowers the server to execute queries that the users requested, and achieves maximum privacy given the mix of queries issued by the users. The database server fully evaluates queries on encrypted data and sends the result back to the client for final decryption; client machines do not perform any query processing and client-side applications run unchanged. Our evaluation shows that CryptDB has modest overhead: on the TPC-C benchmark on Postgres, CryptDB reduces throughput by 27% compared to regular Postgres. Importantly, CryptDB does not change the innards of existing DBMSs: we realized the implementation of CryptDB using client-side query rewriting/encrypting, user-defined functions, and server-side tables for public key information. As such, CryptDB is portable; porting CryptDB to MySQL required changing 86 lines of code, mostly at the connectivity layer

Extending Order Preserving Encryption for Multi-User Systems

Several order preserving encryption (OPE) algorithms have been developed in the literature to support search on encrypted data. However, existing OPE schemes only consider a single encryption key, which is infeasible for a practical system with multiple users (implying that all users should have the single encryption key in order to encrypt or decrypt confidential data). In this paper, we develop the first protocols, DOPE and OE-DOPE, to support the use of OPE in multi-user systems. First, we introduce a group of key agents into the system and invent the DOPE protocol to enable “distributed encryption” to assure that the OPE encryption key is not known by any entity in the system. However, in DOPE, if a key agent is compromised, the share of the secret data that is sent to this key agent is compromised. To solve the problem, we developed a novel oblivious encryption (OE) protocol based on the oblivious transfer concept to deliver and encrypt the shares obliviously. Then, we integrate it with DOPE to obtain the OE-DOPE protocol. Security of OE-DOPE is further enhanced with additional techniques. Both DOPE and OE-DOPE can be used with any existing OPE algorithms while retaining all the advantages of OPE without requiring the users to share the single encryption key, making the OPE approach feasible in practical systems

CryptDB: Protecting confidentiality with encrypted query processing

Online applications are vulnerable to theft of sensitive information because adversaries can exploit software bugs to gain access to private data, and because curious or malicious administrators may capture and leak data. CryptDB is a system that provides practical and provable confidentiality in the face of these attacks for applications backed by SQL databases. It works by executing SQL queries over encrypted data using a collection of efficient SQL-aware encryption schemes. CryptDB can also chain encryption keys to user passwords, so that a data item can be decrypted only by using the password of one of the users with access to that data. As a result, a database administrator never gets access to decrypted data, and even if all servers are compromised, an adversary cannot decrypt the data of any user who is not logged in. An analysis of a trace of 126 million SQL queries from a production MySQL server shows that CryptDB can support operations over encrypted data for 99.5% of the 128,840 columns seen in the trace. Our evaluation shows that CryptDB has low overhead, reducing throughput by 14.5% for phpBB, a web forum application, and by 26% for queries from TPC-C, compared to unmodified MySQL. Chaining encryption keys to user passwords requires 11--13 unique schema annotations to secure more than 20 sensitive fields and 2--7 lines of source code changes for three multi-user web applications.National Science Foundation (U.S.) (CNS-0716273)National Science Foundation (U.S.) (IIS-1065219

Armazenamento distribuído de dados seguros com esquema de consultas diretas

Monografia (graduação)—Universidade de Brasília, Faculdade de Tecnologia, Departamento de Engenharia Elétrica, 2014.O roubo de dados confidenciais é um quesito de extrema relevância para os dias atuais. Na maioria das aplicações, os dados confidenciais são armazenados em servidores. Assim, os sistemas existentes naturalmente tentam impedir os adversários de comprometer esses servidores por meio de controles de acesso. No entanto, estudos têm demonstrado que os adversários ainda assim tentam encontrar uma maneira para invadir e roubar os dados. Com o intuito de impedir a invasão e descoberta de dados sigilosos, uma nova abordagem é apresentada para proteger a confidencialidade dos dados mesmo quando os atacantes tenham acesso a todos os dados do servidor: a construção de sistemas práticos e seguros que realizem consultas e inserções em dados criptografados sem acesso a chave de decodificação. Este trabalho propõe um modelo de implantação que permita um meio de acesso comprovadamente seguro, tanto na atualização quanto na consulta a dados, com perda de eficiência tolerada em suas transações, isto é, com menor interferência em seu desempenho possível. O modelo previsto é aplicado em um cenário real: um sistema distribuído hospedado pelo Google (Encrypted BigQuery), que abarca o uso de criptografia em dados que são armazenados de forma distribuída em bancos de dados não-relacionais desenvolvido para o tratamento massivo de dados. Como resultado, é mostrado que estes sistemas suportam uma variedade de aplicações com baixo custo operacional. ___________________________________________________________________________ ABSTRACTTheft of confidential information is a question of extreme relevance to the present day. In most applications, sensitive data are stored on servers. Thus, existing systems naturally try to prevent adversaries from compromising these servers through access controls. However, studies have shown that adversaries still find a way to break in and steal data. In order to prevent the invasion and discovery of sensitive data, a new approach is presented to protecting the confidentiality of data even when the attackers have access to all data from the server: building practical and reliable systems that perform queries and inserts on encrypted data without the decryption key. This work proposes a deployment model that provide for a proven safe means of access, both in the update query as the data, with efficiency loss tolerated in their transactions, ie, with as less interference on your performance as possible. The model set is applied in a real scenario: a distributed system hosted by Google (Encrypted BigQuery), which includes the use of encryption in data stored in non-relational databases developed for massive data processing. As a result, it is shown that these systems support a variety of applications with low overhead

Exécutions de requêtes respectueuses de la vie privée par utilisation de composants matériels sécurisés

Current applications, from complex sensor systems (e.g. quantified self) to online e-markets acquire vast quantities of personal information which usually end-up on central servers. This massive amount of personal data, the new oil, represents an unprecedented potential for applications and business. However, centralizing and processing all one's data in a single server, where they are exposed to prying eyes, poses a major problem with regards to privacy concern.Conversely, decentralized architectures helping individuals keep full control of their data, but they complexify global treatments and queries, impeding the development of innovative services.In this thesis, we aim at reconciling individual's privacy on one side and global benefits for the community and business perspectives on the other side. It promotes the idea of pushing the security to secure hardware devices controlling the data at the place of their acquisition. Thanks to these tangible physical elements of trust, secure distributed querying protocols can reestablish the capacity to perform global computations, such as SQL aggregates, without revealing any sensitive information to central servers.This thesis studies the subset of SQL queries without external joins and shows how to secure their execution in the presence of honest-but-curious attackers. It also discusses how the resulting querying protocols can be integrated in a concrete decentralized architecture. Cost models and experiments on SQL/AA, our distributed prototype running on real tamper-resistant hardware, demonstrate that this approach can scale to nationwide applications.Les applications actuelles, des systèmes de capteurs complexes (par exemple auto quantifiée) aux applications de e-commerce, acquièrent de grandes quantités d'informations personnelles qui sont habituellement stockées sur des serveurs centraux. Cette quantité massive de données personnelles, considéré comme le nouveau pétrole, représente un important potentiel pour les applications et les entreprises. Cependant, la centralisation et le traitement de toutes les données sur un serveur unique, où elles sont exposées aux indiscrétions de son gestionnaire, posent un problème majeur en ce qui concerne la vie privée.Inversement, les architectures décentralisées aident les individus à conserver le plein de contrôle sur leurs données, toutefois leurs traitements en particulier le calcul de requêtes globales deviennent complexes.Dans cette thèse, nous visons à concilier la vie privée de l'individu et l'exploitation de ces données, qui présentent des avantages manifestes pour la communauté (comme des études statistiques) ou encore des perspectives d'affaires. Nous promouvons l'idée de sécuriser l'acquisition des données par l'utilisation de matériel sécurisé. Grâce à ces éléments matériels tangibles de confiance, sécuriser des protocoles d'interrogation distribués permet d'effectuer des calculs globaux, tels que les agrégats SQL, sans révéler d'informations sensibles à des serveurs centraux.Cette thèse étudie le sous-groupe de requêtes SQL sans jointures et montre comment sécuriser leur exécution en présence d'attaquants honnêtes-mais-curieux. Cette thèse explique également comment les protocoles d'interrogation qui en résultent peuvent être intégrés concrètement dans une architecture décentralisée. Nous démontrons que notre approche est viable et peut passer à l'échelle d'applications de la taille d'un pays par un modèle de coût et des expériences réelles sur notre prototype, SQL/AA