Valter Balegas, Diogo Serra, S. Duarte, Carla Ferreira, M. Shapiro, R. Rodrigues, Nuno M. Preguiça
{"title":"Extending Eventually Consistent Cloud Databases for Enforcing Numeric Invariants","authors":"Valter Balegas, Diogo Serra, S. Duarte, Carla Ferreira, M. Shapiro, R. Rodrigues, Nuno M. Preguiça","doi":"10.1109/SRDS.2015.32","DOIUrl":"https://doi.org/10.1109/SRDS.2015.32","url":null,"abstract":"Geo-replicated databases often offer high availability and low latency by relying on weak consistency models. The inability to enforce invariants across all replicas remains a key shortcoming that prevents the adoption of such databases in several applications. In this paper we show how to extend an eventually consistent cloud database for enforcing numeric invariants. Our approach builds on ideas from escrow transactions, but our novel design overcomes the limitations of previous works. First, by relying on a new replicated data type, our design has no central authority and uses pairwise asynchronous communication only. Second, by layering our design on top of a fault-tolerant database, our approach exhibits better availability during network partitions and data center faults. The evaluation of our prototype, built on top of Riak, shows much lower latency and better scalability than the traditional approach of using strong consistency to enforce numeric invariants.","PeriodicalId":244925,"journal":{"name":"2015 IEEE 34th Symposium on Reliable Distributed Systems (SRDS)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122630297","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Bernardo Ferreira, João Rodrigues, J. Leitao, H. Domingos
{"title":"Privacy-Preserving Content-Based Image Retrieval in the Cloud","authors":"Bernardo Ferreira, João Rodrigues, J. Leitao, H. Domingos","doi":"10.1109/SRDS.2015.27","DOIUrl":"https://doi.org/10.1109/SRDS.2015.27","url":null,"abstract":"Storage requirements for visual data have been increasing in recent years, following the emergence of many new highly interactive multimedia services and applications for both personal and corporate use. This has been a key driving factor for the adoption of cloud-based data outsourcing solutions. However, outsourcing data storage to the Cloud also leads to new challenges that must be carefully addressed, especially regarding privacy. In this paper we propose a secure framework for outsourced privacy-preserving storage and retrieval in large image repositories. Our proposal is based on IES-CBIR, a novel Image Encryption Scheme that displays Content-Based Image Retrieval properties. Our solution enables both encrypted storage and searching using CBIR queries while preserving privacy. We have built a prototype of the proposed framework, formally analyzed and proven its security properties, and experimentally evaluated its performance and precision. Our results show that IES-CBIR is provably secure, allows more efficient operations than existing proposals, both in terms of time and space complexity, and enables more reliable practical application scenarios.","PeriodicalId":244925,"journal":{"name":"2015 IEEE 34th Symposium on Reliable Distributed Systems (SRDS)","volume":"287 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125223756","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}