In today's Internet, with the advent of cloud computing, there is a natural desire for enterprises, organizations, and end users to outsource increasingly large amounts of data to a cloud provider. Therefore, ensuring security and privacy is becoming a significant challenge for cloud computing, especially for users with sensitive and valuable data. Recently, many efficient and scalable query processing methods over encrypted data have been proposed. Despite that, numerous challenges remain to be addressed due to the high complexity of many important queries on encrypted large-scale datasets. This thesis studies the problem of privacy-preserving database query processing on structured data (e.g., relational and graph databases). In particular, this thesis proposes several practical and provable secure structured encryption schemes that allow the data owner to encrypt data without losing the ability to query and retrieve it efficiently for authorized clients. This thesis includes two parts. The first part investigates graph encryption schemes. This thesis proposes a graph encryption scheme for approximate shortest distance queries. Such scheme allows the client to query the shortest distance between two nodes in an encrypted graph securely and efficiently. Moreover, this thesis also explores how the techniques can be applied to other graph queries. The second part of this thesis proposes secure top-k query processing schemes on encrypted relational databases. Furthermore, the thesis develops a scheme for the top-k join queries over multiple encrypted relations. Finally, this thesis demonstrates the practicality of the proposed encryption schemes by prototyping the encryption systems to perform queries on real-world encrypted datasets.

Submitted by SBI Biblioteca Digital (sbi.bibliotecadigital@puc-campinas.edu.br) on 2017-01-19T13:28:00Z No. of bitstreams: 1 Silvana Bordini Coca Machado.pdf: 2197792 bytes, checksum: e1d90aedeee97ffbdaa9adcd79a31400 (MD5) / Made available in DSpace on 2017-01-19T13:28:00Z (GMT). No. of bitstreams: 1 Silvana Bordini Coca Machado.pdf: 2197792 bytes, checksum: e1d90aedeee97ffbdaa9adcd79a31400 (MD5) Previous issue date: 2016-11-28 / According to the United Nations report, 2014, for the first time in history, most of the world's population is living in urban centers. The urbanization movement, from 1950 to the present day, presented a migration from rural areas to urban almost doubling the reality of that time, which was 30%. And by 2050, it is expected that to be over 66% urban population. That is, the available infrastructure and services should be sized to meet this rapid growth and in less than a century. The information from these citizens, requiring for services provision of care for health, education, transportation and security, are stored in various systems, which may not part of any data centralization and standardization. Many data feature personal information, such as national registers, addresses, and others, which are not well safeguarded and can be a door to the leakage and misuse. The technologies used for the collection and storage of data can affect significantly the lives of people by emerging problems with security and data privacy. The ISO 27001 standard defines the triple constraint for information security through confidentiality, integrity and availability. In order to take the emergence of Smart Cities in the context, which are based on the provision of services via communication highways and by which provide information to governmental agencies, institutions in general and to every citizen. This study aims to learn how to make proper use of data personal institutions under security protection. In this context, they are seeking transparency and agility through ICT, which can be seen during this study that effective confidentiality requires even greater attention from managers and any team responsible for collecting, processing and distributing information. This result for this research is the proposition of a method for public organizations on how to handle data and information related to privacy, using a method based on decision making with the Analytic Hierarchy Process (AHP) and data subsets evaluation. / Segundo relat?rio da ONU, Organiza??o das Na??es Unidas, de 2014, pela primeira vez na hist?ria, a maior parte da popula??o mundial est? vivendo em centros urbanos. O movimento de urbaniza??o, desde 1950 at? os dias atuais, apresentou uma imigra??o da ?rea rural para a urbana quase dobrando a realidade daquela ?poca, a qual era de 30%, e at? 2050, espera-se uma popula??o urbana superior a 66%. A infra-estrutura e os servi?os oferecidos dever?o estar dimensionados para atender a este aumento populacional. A informa??o destes cidad?os, necess?ria para provimento de atendimentos n?o apenas da sa?de, educa??o, transporte e seguran?a s?o armazenadas nos mais diversos sistemas, sem que haja obrigatoriamente uma centraliza??o e padroniza??o destes dados. Muitos dados caracterizam informa??es pessoais, como registros nacionais, endere?os, que devem ser salvo-guardados adequadamente, caso contr?rio, podem ser uma porta para o vazamento e mal-uso dos mesmos. As tecnologias utilizadas para coleta e armazenamento dos dados podem afetar sensivelmente a vida da popula??o surgindo ent?o os problemas com a seguran?a e a privacidade de dados. A norma ISO 27001 define o trip? da seguran?a da informa??o por meio da confidencialidade, integridade e disponibilidade, buscando contextualizar a emerg?ncia das Cidades Inteligentes, que se fundamentam na oferta de servi?os via infovias de comunica??o e pelas quais s?o disponibilizadas informa??es a ?rg?os governamentais, institui??es em geral e a todo cidad?o. Este trabalho tem por objetivo apreender como fazer o uso adequado de dados pessoais nas institui??es, perante esta ?tica de prote??o, ao mesmo tempo em que, principalmente, com rela??o aos ?rg?os p?blicos se exige transpar?ncia. Nesse contexto em que se busca transpar?ncia e agilidade por meio das tecnologias da informa??o e comunica??o, se observar? no decorrer desta pesquisa que efetivos cuidados com a confidencialidade exigem ainda maior aten??o dos gestores e respons?veis pela coleta, processamento e distribui??o da informa??o. O resultado obtido foi a proposi??o de uma metodologia para o tratamento de dados e informa??es privadas pelas institui??es p?blicas, utilizando-se modelo de apoio a decis?o Analytical Hierachical Process (AHP) e avalia??o de subconjuntos de dados.