DOCSLIB.ORG

Secure Multi Keyword Fuzzy with Semantic Expansion Based Search Over Encrypted Cloud Data

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Secure Multi Keyword Fuzzy with Semantic Expansion Based Search Over Encrypted Cloud Data SECURE MULTI KEYWORD FUZZY WITH SEMANTIC EXPANSION BASED SEARCH OVER ENCRYPTED CLOUD DATA ARFA BAIG Dept of Computer Science & Engineering B.N.M Institute of Technology, Bangalore, India E-mail: [email protected] Abstract— The initiation of cloud computing has led to ease of access in Internet-based computing and is commonly used for web servers or development systems where there are security and compliance requirements. Nevertheless, some of the confidential information has to be encrypted to avoid any intrusion. Henceforward as an attempt, a semantic expansion based multi- keyword fuzzy search provides solution over encrypted cloud data by using the locality-sensitive hashing technique. This solution returns not only the accurately matched files, but also the files including the terms semantically related to the query keyword. In the proposed scheme fuzzy matching is achieved through algorithmic design rather than expanding the index files. It also eradicates the need of a predefined dictionary and effectively supports multiple keyword fuzzy search without increasing the index or search complexity. The indexes are formed based on locality sensitive hashing (LSH), the result files are returned according to the total relevance score. Index Terms—Multi keyword fuzzy search, Locality Sensitive Hashing, Secure Semantic Expansion. support fuzzy search and also required the use of pre- I. INTRODUCTION defined dictionary which lacked scalability and Cloud computing is a form of computing that depends flexibility for modification and updation of the data. on sharing computing resources rather than having These drawbacks create the necessity of the new local servers or personal devices to handle technique of multi keyword fuzzy search. applications. The public cloud deployments are Thus from a new perception semantic expansion commonly used for web servers or development based multi keyword fuzzy search reinforces the systems where security and compliance requirements system usability by returning the exactly matched of larger organizations and their customers is not an files and the files including the terms semantically issue. In cloud computing, scalable and pliant storage related to the query keyword, which boosts the search and computation resources are provisioned as flexibility and usability. measured services through the Internet. Cloud Fuzzy searching will find a word even if it is computing empowers cloud customers to enjoy the misspelled. For instance, a fuzzy search for apple will on-demand high quality applications and services find appple. Fuzzy searching can be beneficial for from a centralized pool of configurable computing searching text that may contain typographical errors. resources. This technique can dismiss the burden of Multi-keyword search scheme abolishes the storage management which allows universal data requirement of a predefined keyword dictionary and access with independent geographical locations, and accomplishes this by several novel designs based on avoid capital spending on hardware, software, and locality-sensitive hashing which is secure, efficient personnel maintenances, etc. and accurate. To diminish the risk of data leakage to the cloud service providers, the straight forward solution to II. RELATED WORK implement data privacy is to encrypt sensitive data before being outsourced. Unfortunately, data A. Privacy preserving multi-keyword text search in encryption, if not carried out appropriately and may the cloud supporting similarity based ranking reduce the efficiency of data utilization. Typically, a With the increasing popularity of cloud computing, user reclaims files of interest to him/her via keyword huge amount of documents are outsourced to the search instead of retrieving back all the file such as cloud for reduced management cost and ease of keyword based search technique has been extensively access. Although encryption helps protecting user used in the daily life, e.g. Google plaintext keyword data confidentiality, it leaves the well-functioning yet search. Nonetheless, the technologies are invalid after practically-efficient secure search functions over the keywords are encrypted. encrypted data a challenging problem. The paper Fuzzy search using symmetric encryption has been a presents a privacy-preserving multi-keyword text challenge as it was being carried out using single search (MTS) scheme with similarity-based ranking exact keyword only and there had been use of to address this problem. To support multi-keyword inverted indexes as well which were not so search and search result ranking, a search index based proficient. In order to preserve the privacy of the on term frequency and the vector space model is query keyword cosine similarity measurement has proposed along with cosine similarity measure to been used for the multi keyword search but it did not achieve higher search result accuracy. To improve the Proceedings of 14th IRF International Conference, Bengaluru, India, 31st May 2015, ISBN: 978-93-85465-25-3 66 Secure Multi Keyword Fuzzy With Semantic Expansion Based Search Over Encrypted Cloud Data search efficiency, a tree-based index structure and into two steps. The first step finds the candidate list in various adaption methods for multi-dimensional terms of secure pruning codes. In particular, two (MD) algorithm is proposed so that the practical methods are developed to construct these pruning search efficiency is much better than that of linear codes. The second step uses a semi honest third party search. To further enhance the search privacy, two to determine the best matching keyword depending secure index schemes are used to meet the stringent on secure similarity function. This intends to reveal privacy requirements under strong threat models, i.e., as little information as possible to that third party and known cipher text model and known background hopes that developing such a system will enhance the model. Finally, the effectiveness and efficiency of the utilization of retrieval information systems and make proposed scheme are demonstrated through extensive these systems more user-friendly. experimental evaluation. III. EXISTING SYSTEM B. Public key encryption with keyword search. The problem of searching on data that is encrypted It is desired to store data on data storage servers such using a public key system is studied. Considering as mail servers and file servers in encrypted form to user Bob who sends email to user Alice encrypted reduce security and privacy risks. But this generally under Alice’s public key. An email gateway wants to implies that one has to detriment functionality for test whether the email contains the keyword “urgent” security. For example, if a client wishes to reclaim so that it could route the email accordingly. only documents containing certain words, it was not Alice, on the other hand does not wish to give the earlier known how to let the data storage server gateway the ability to decrypt all her messages. This perform the search and answer the query without loss defines and constructs a mechanism that enables of data confidentiality. Here the cryptographic Alice to provide a key to the gateway that enables the schemes for the problem of searching on encrypted gateway to test whether the word “urgent” is a data is carried out and provide proofs of security for keyword in the email without learning anything else the resulting cryptosystems. This technique has a about the email. The paper refers to the mechanism number of essential advantages. Provably secure: this as Public Key Encryption with keyword Search. As scheme provides secrecy for encryption, such that the another example, consider a mail server that stores untrusted server cannot acquire anything about the various messages publicly encrypted for Alice by plain text when only given the cipher text. Provides others. Using the mechanism Alice can send the mail query isolation for searches which means that the server a key that will enable the server to identify all untrusted server cannot learn anything more about the messages containing some specific keyword, but plain text than the search result. Controlled searching learn nothing else. The paper defines the concept of is carried out so that the untrusted server cannot public key encryption with keyword search and gives search for an arbitrary word without the user’s several constructions. authorization; they also support hidden queries, such that the user may ask the untrusted server to search C. Approximate Keyword-based Search over for a secret word without revealing the word to the Encrypted Cloud Data server. This scheme didn’t contain an index, thus, the To protect the privacy, users have to encrypt their search operation went through the entire file. sensitive data before outsourcing it to the cloud. However, the traditional encryption schemes are inadequate since they make the application of indexing and searching operations more challenging tasks. Accordingly, searchable encryption systems are developed to conduct search operations over a set of encrypted data. Unfortunately, these systems only allow their clients to perform an exact search but not approximate search, an important need for all the current information retrieval systems. Recently, an increased attention has been paid to the approximate searchable encryption systems to find keywords that match the submitted queries approximately. This work focuses on constructing a flexible secure index that allows the cloud server to perform the Fig1: Working
Load more

Recommended publications
  • Lower Bounds on Lattice Sieving and Information Set Decoding
    Lower bounds on lattice sieving and information set decoding Elena Kirshanova1 and Thijs Laarhoven2 1Immanuel Kant Baltic Federal University, Kaliningrad, Russia [email protected] 2Eindhoven University of Technology, Eindhoven, The Netherlands [email protected] April 22, 2021 Abstract In two of the main areas of post-quantum cryptography, based on lattices and codes, nearest neighbor techniques have been used to speed up state-of-the-art cryptanalytic algorithms, and to obtain the lowest asymptotic cost estimates to date [May{Ozerov, Eurocrypt'15; Becker{Ducas{Gama{Laarhoven, SODA'16]. These upper bounds are useful for assessing the security of cryptosystems against known attacks, but to guarantee long-term security one would like to have closely matching lower bounds, showing that improvements on the algorithmic side will not drastically reduce the security in the future. As existing lower bounds from the nearest neighbor literature do not apply to the nearest neighbor problems appearing in this context, one might wonder whether further speedups to these cryptanalytic algorithms can still be found by only improving the nearest neighbor subroutines. We derive new lower bounds on the costs of solving the nearest neighbor search problems appearing in these cryptanalytic settings. For the Euclidean metric we show that for random data sets on the sphere, the locality-sensitive filtering approach of [Becker{Ducas{Gama{Laarhoven, SODA 2016] using spherical caps is optimal, and hence within a broad class of lattice sieving algorithms covering almost all approaches to date, their asymptotic time complexity of 20:292d+o(d) is optimal. Similar conditional optimality results apply to lattice sieving variants, such as the 20:265d+o(d) complexity for quantum sieving [Laarhoven, PhD thesis 2016] and previously derived complexity estimates for tuple sieving [Herold{Kirshanova{Laarhoven, PKC 2018].
    [Show full text]
  • Efficient (Ideal) Lattice Sieving Using Cross-Polytope
    Efficient (ideal) lattice sieving using cross-polytope LSH Anja Becker1 and Thijs Laarhoven2? 1 EPFL, Lausanne, Switzerland | [email protected] 2 TU/e, Eindhoven, The Netherlands | [email protected] Abstract. Combining the efficient cross-polytope locality-sensitive hash family of Terasawa and Tanaka with the heuristic lattice sieve algorithm of Micciancio and Voulgaris, we show how to obtain heuristic and prac- tical speedups for solving the shortest vector problem (SVP) on both arbitrary and ideal lattices. In both cases, the asymptotic time complex- ity for solving SVP in dimension n is 20:298n+o(n). For any lattice, hashes can be computed in polynomial time, which makes our CPSieve algorithm much more practical than the SphereSieve of Laarhoven and De Weger, while the better asymptotic complexities imply that this algorithm will outperform the GaussSieve of Micciancio and Voulgaris and the HashSieve of Laarhoven in moderate dimensions as well. We performed tests to show this improvement in practice. For ideal lattices, by observing that the hash of a shifted vector is a shift of the hash value of the original vector and constructing rerandomiza- tion matrices which preserve this property, we obtain not only a linear decrease in the space complexity, but also a linear speedup of the overall algorithm. We demonstrate the practicability of our cross-polytope ideal lattice sieve IdealCPSieve by applying the algorithm to cyclotomic ideal lattices from the ideal SVP challenge and to lattices which appear in the cryptanalysis of NTRU. Keywords: (ideal) lattices, shortest vector problem, sieving algorithms, locality-sensitive hashing 1 Introduction Lattice-based cryptography.
    [Show full text]
  • Murari Lal (India), Hideo Harasawa (Japan), and Daniel Murdiyarso (Indonesia)
    11 Asia MURARI LAL (INDIA), HIDEO HARASAWA (JAPAN), AND DANIEL MURDIYARSO (INDONESIA) Lead Authors: W.N. Adger (UK), S. Adhikary (Nepal), M. Ando (Japan), Y. Anokhin (Russia), R.V. Cruz (Philippines), M. Ilyas (Malaysia), Z. Kopaliani (Russia), F. Lansigan (Philippines), Congxian Li (China), A. Patwardhan (India), U. Safriel (Israel), H. Suharyono (Indonesia), Xinshi Zhang (China) Contributing Authors: M. Badarch (Mongolia), Xiongwen Chen (China), S. Emori (Japan), Jingyun Fang (China), Qiong Gao (China), K. Hall (USA), T. Jarupongsakul (Thailand), R. Khanna-Chopra (India), R. Khosa (India), M.P. Kirpes (USA), A. Lelakin (Russia), N. Mimura (Japan), M.Q. Mirza (Bangladesh), S. Mizina (Kazakhstan), M. Nakagawa (Japan), M. Nakayama (Japan), Jian Ni (China), A. Nishat (Bangladesh), A. Novoplansky (Israel), T. Nozawa (Japan), W.T . Piver (USA), P.S. Ramakrishnan (India), E. Rankova (Russia), T.L. Root (USA), D. Saltz (Israel), K.P. Sharma (Nepal), M.L. Shrestha (Nepal), G. Srinivasan (India), T.S. Teh (Malaysia), Xiaoping Xin (China), M. Yoshino (Japan), A. Zangvil (Israel), Guangsheng Zhou (China) Review Editors: Su Jilan (China) and T. Ososkova (Uzbekistan) CONTENTS Executive Summary 53 5 11. 2 . 4 . Oceanic and Coastal Ecosystems 56 6 11. 2 . 4 . 1 . Oceans and Coastal Zones 56 6 11. 1 . The Asian Region 53 9 11. 2 . 4 . 2 . Deltas, Estuarine, 11. 1 . 1 . Ba c k g r o u n d 53 9 and Other Coastal Ecosystems 56 7 11. 1 . 2 . Physical and Ecological Features 53 9 11.2.4.3. Coral Reefs 56 7 11. 1 . 2 . 1 . Regional Zonation 53 9 11.2.4.4.
    [Show full text]
  • Efficient Similarity Search Over Encrypted Data
    Efficient Similarity Search over Encrypted Data Mehmet Kuzu, Mohammad Saiful Islam, Murat Kantarcioglu Department of Computer Science, The University of Texas at Dallas Richardson, TX 75080, USA {mehmet.kuzu, saiful, muratk} @ utdallas.edu Abstract— In recent years, due to the appealing features of A similarity search problem consists of a collection of data cloud computing, large amount of data have been stored in the items that are characterized by some features, a query that cloud. Although cloud based services offer many advantages, specifies a value for a particular feature and a similarity metric privacy and security of the sensitive data is a big concern. To mitigate the concerns, it is desirable to outsource sensitive data to measure the relevance between the query and the data items. in encrypted form. Encrypted storage protects the data against The goal is to retrieve the items whose similarity against the illegal access, but it complicates some basic, yet important func- specified query is greater than a predetermined threshold under tionality such as the search on the data. To achieve search over the utilized metric. Although exact matching based searchable encrypted data without compromising the privacy, considerable encryption methods are not suitable to achieve this goal, there amount of searchable encryption schemes have been proposed in the literature. However, almost all of them handle exact query are some sophisticated cryptographic techniques that enable matching but not similarity matching; a crucial requirement similarity search over encrypted data [9], [10]. Unfortunately, for real world applications. Although some sophisticated secure such secure multi-party computation based techniques incur multi-party computation based cryptographic techniques are substantial computational resources.
    [Show full text]
  • Implementation of Locality Sensitive Hashing Techniques
    Implementation of Locality Sensitive Hashing Techniques Project Report submitted in partial fulfillment of the requirement for the degree of Bachelor of Technology. in Computer Science & Engineering under the Supervision of Dr. Nitin Chanderwal By Srishti Tomar(111210) to Jaypee University of Information and TechnologyWaknaghat, Solan – 173234, Himachal Pradesh i Certificate This is to certify that project report entitled “Implementaion of Locality Sensitive Hashing Techniques”, submitted by Srishti Tomar in partial fulfillment for the award of degree of Bachelor of Technology in Computer Science & Engineering to Jaypee University of Information Technology, Waknaghat, Solan has been carried out under my supervision. This work has not been submitted partially or fully to any other University or Institute for the award of this or any other degree or diploma. Date: Supervisor’s Name: Dr. Nitin Chanderwal Designation : Associate Professor ii Acknowledgement I am highly indebted to Jaypee University of Information Technology for their guidance and constant supervision as well as for providing necessary information regarding the project & also for their support in completing the project. I would like to express my gratitude towards my parents & Project Guide for their kind co-operation and encouragement which help me in completion of this project. I would like to express my special gratitude and thanks to industry persons for giving me such attention and time. My thanks and appreciations also go to my colleague in developing the project and people who have willingly helped me out with their abilities Date: Name of the student: Srishti Tomar iii Table of Content S. No. Topic Page No. 1. Abstract 1 2.
    [Show full text]
  • Evaluation of Scalable Pprl Schemes with a Native Lsh Database Engine
    EVALUATION OF SCALABLE PPRL SCHEMES WITH A N ATIVE LSH DATABASE ENGINE Dimitrios Karapiperis 1, Chris T. Panagiotakopoulos 2 and Vassilios S. Verykios 3 1School of Science and Technology, Hellenic Open University, Greece 2Department of Primary Education, University of Patras, Greece 3School of Science and Technology, Hellenic Open University, Greece ABSTRACT In this paper, we present recent work which has been accomplished in the newly introduced research area of privacy preserving record linkage, and then, we present our L-fold redundant blocking scheme, that relies on the Locality-Sensitive Hashing technique for identifying similar records. These records have undergone an anonymization transformation using a Bloom filter- based encoding technique. We perform an experimental evaluation of our state-of-the-art blocking method against four other rival methods and present the results by using LSHDB, a newly introduced parallel and distributed database engine. KEYWORDS Locality-Sensitive Hashing, Record Linkage, Privacy-Preserving Record Linkage, Entity Resolution 1. INTRODUCTION A series of economic collapses of bank and insurance companies recently triggered a financial crisis of unprecedented severity. In order for these institutions to get back on their feet, they had to engage in merger talks inevitably. One of the tricky points for such mergers is to be able to estimate the extent to which the customer bases of the constituent institutions are in common, so that the benefits of the merger can be proactively assessed. The process of comparing the customer bases and finding out records that refer to the same real world entity, is known as the Record Linkage , the Entity Resolution or the Data Matching problem.
    [Show full text]
  • Crypto-Aided MAP Detection and Mitigation of False Data in Wireless Relay Networks
    Iowa State University Capstones, Theses and Graduate Theses and Dissertations Dissertations 2019 Crypto-aided MAP detection and mitigation of false data in wireless relay networks Xudong Liu Iowa State University Follow this and additional works at: https://lib.dr.iastate.edu/etd Part of the Communication Commons Recommended Citation Liu, Xudong, "Crypto-aided MAP detection and mitigation of false data in wireless relay networks" (2019). Graduate Theses and Dissertations. 17730. https://lib.dr.iastate.edu/etd/17730 This Dissertation is brought to you for free and open access by the Iowa State University Capstones, Theses and Dissertations at Iowa State University Digital Repository. It has been accepted for inclusion in Graduate Theses and Dissertations by an authorized administrator of Iowa State University Digital Repository. For more information, please contact [email protected]. Crypto-aided MAP detection and mitigation of false data in wireless relay networks by Xudong Liu A dissertation submitted to the graduate faculty in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY Major: Electrical Engineering (Communications and Signal Processing) Program of Study Committee: Sang Wu Kim, Major Professor Yong Guan Chinmay Hegde Thomas Daniels Long Que The student author, whose presentation of the scholarship herein was approved by the program of study committee, is solely responsible for the content of this dissertation. The Graduate College will ensure this dissertation is globally accessible and will not permit alterations after a degree is conferred. Iowa State University Ames, Iowa 2019 Copyright c Xudong Liu, 2019. All rights reserved. ii DEDICATION I would like to dedicate this thesis to my beloved wife Yu Wang, without her emotional support I would not be able to complete this work.
    [Show full text]
  • Symmetric Cryptography
    Symmetric Cryptography CS461/ECE422 Fall 2010 1 Outline • Overview of Cryptosystem design • Commercial Symmetric systems – DES – AES • Modes of block and stream ciphers 2 Reading • Chapter 9 from Computer Science: Art and Science – Sections 3 and 4 • AES Standard issued as FIPS PUB 197 – http://csrc.nist.gov/publications/fips/fips197/fips-197.pdf • Handbook of Applied Cryptography, Menezes, van Oorschot, Vanstone – Chapter 7 – http://www.cacr.math.uwaterloo.ca/hac/ 3 Stream, Block Ciphers • E encipherment function – Ek(b) encipherment of message b with key k – In what follows, m = b1b2 …, each bi of fixed length • Block cipher – Ek(m) = Ek(b1)Ek(b2) … • Stream cipher – k = k1k2 … – Ek(m) = Ek1(b1)Ek2(b2) … – If k1k2 … repeats itself, cipher is periodic and the length of its period is one cycle of k k … 1 2 4 Examples • Vigenère cipher – |bi| = 1 character, k = k1k2 … where |ki| = 1 character – Each bi enciphered using ki mod length(k) – Stream cipher • DES – |bi| = 64 bits, |k| = 56 bits – Each bi enciphered separately using k – Block cipher 5 Confusion and Diffusion • Confusion – Interceptor should not be able to predict how ciphertext will change by changing one character • Diffusion – Cipher should spread information from plaintext over cipher text – See avalanche effect 6 Avalanche Effect • Key desirable property of an encryption algorithm • Where a change of one input or key bit results in changing approx half of the output bits • If the change were small, this might provide a way to reduce the size of the key space to be searched
    [Show full text]
  • Hashing Techniques: a Survey and Taxonomy
    11 Hashing Techniques: A Survey and Taxonomy LIANHUA CHI, IBM Research, Melbourne, Australia XINGQUAN ZHU, Florida Atlantic University, Boca Raton, FL; Fudan University, Shanghai, China With the rapid development of information storage and networking technologies, quintillion bytes of data are generated every day from social networks, business transactions, sensors, and many other domains. The increasing data volumes impose significant challenges to traditional data analysis tools in storing, processing, and analyzing these extremely large-scale data. For decades, hashing has been one of the most effective tools commonly used to compress data for fast access and analysis, as well as information integrity verification. Hashing techniques have also evolved from simple randomization approaches to advanced adaptive methods considering locality, structure, label information, and data security, for effective hashing. This survey reviews and categorizes existing hashing techniques as a taxonomy, in order to provide a comprehensive view of mainstream hashing techniques for different types of data and applications. The taxonomy also studies the uniqueness of each method and therefore can serve as technique references in understanding the niche of different hashing mechanisms for future development. Categories and Subject Descriptors: A.1 [Introduction and Survey]: Hashing General Terms: Design, algorithms Additional Key Words and Phrases: Hashing, compression, dimension reduction, data coding, cryptographic hashing ACM Reference Format: Lianhua Chi and Xingquan Zhu. 2017. Hashing techniques: A survey and taxonomy. ACM Comput. Surv. 50, 1, Article 11 (April 2017), 36 pages. DOI: http://dx.doi.org/10.1145/3047307 1. INTRODUCTION Recent advancement in information systems, including storage devices and networking techniques, have resulted in many applications generating large volumes of data and requiring large storage, fast delivery, and quick analysis.
    [Show full text]
  • Comparison of Hash Function Algorithms Against Attacks: a Review
    (IJACSA) International Journal of Advanced Computer Science and Applications, Vol. 9, No. 8, 2018 Comparison of Hash Function Algorithms Against Attacks: A Review Ali Maetouq, Salwani Mohd Daud, Noor Azurati Ahmad, Nurazean Maarop, Nilam Nur Amir Sjarif, Hafiza Abas Advanced Informatics Department Razak Faculty of Technology and Informatics Universiti Teknologi Malaysia Kuala Lumpur, Malaysia Abstract—Hash functions are considered key components of H: {0, 1}* → {0, 1}n (1) nearly all cryptographic protocols, as well as of many security applications such as message authentication codes, data integrity, Where, {0, 1}* refers to the set of binary elements of any password storage, and random number generation. Many hash length including the empty string. Meanwhile, {0, 1}n is used function algorithms have been proposed in order to ensure to refer to a set of binary elements with length n. Thus, a set of authentication and integrity of the data, including MD5, SHA-1, fixed-length binary elements is mapped to arbitrary-length SHA-2, SHA-3 and RIPEMD. This paper involves an overview of binary elements using the hash function. these standard algorithms, and also provides a focus on their limitations against common attacks. These study shows that these The organization of the paper is as follows. In Sections II standard hash function algorithms suffer collision attacks and and III, the basic concepts such as security properties and time inefficiency. Other types of hash functions are also applications of hash functions are discussed. A literature highlighted in comparison with the standard hash function review on the most popular hash function algorithms is algorithm in performing the resistance against common attacks.
    [Show full text]
  • 2021-2022 Bulletin
    Columbia | Engineering Columbia 2021 –2022 500 West 120th Street New York, NY 10027 BULLETIN 2021– 2022 Academic Calendar 2021–2022 The following Academic Calendar was correct and complete when compiled; however, the University reserves the right to revise or amend it, in whole or in part, at any time. Information on the current Academic Calendar may be obtained in the Student Service Center, 205 Kent, 212-854-4330, or visit registrar.columbia.edu. FALL TERM 2021 SPRING TERM 2022 August January 24–26; Sept. 2–6 Registration by appointment (undergraduate) 4–7, 10–14 Registration by appointment (undergraduate and 27–Sept. 10 Graduate orientation and graduate department graduate) orientations TBA Graduate orientation 29–Sept. 8 New student orientation program 17 Birthday of Martin Luther King Jr., 31–Sept. 2 Registration by appointment (graduate) University holiday 18 First day of classes September 18–31 Change of program by appointment (weekdays) 1 Last Day to apply for October degrees 22 Deadline to add spring courses 6 Labor Day, University holiday UNDERGRADUATE ADMISSIONS Need more information? 9 First day of classes February Office of Undergraduate Admissions You can find the contact information 9–21 Change of program by appointment (weekdays) 9 February degrees conferred 212 Hamilton Hall, Mail Code 2807 in the Columbia University Resource List 21 Last day to (1) register for academic credit, (2) change course programs, (3) submit written March 1130 Amsterdam Avenue on pages 226–228 or visit the Columbia Engineering 7 Midterm date website, engineering.columbia.edu. notice of withdrawal from the fall term to the Dean New York, NY 10027 of Student Affairs for full refund of tuition and 14–18 Spring recess Phone: 212-854-2522 special fees, (4) drop Core Curriculum classes.
    [Show full text]
  • A Unified Framework for Secure Search Over Encrypted Cloud Data
    A Unified Framework for Secure Search Over Encrypted Cloud Data Cengiz Orencik∗1, Erkay Savasy2 and Mahmoud Alewiwiz2 1Beykent University, Istanbul, Turkey 2Sabanci University, Istanbul, Turkey May 26, 2017 Abstract This paper presents a unified framework that supports different types of privacy-preserving search queries over encrypted cloud data. In the framework, users can perform any of the multi-keyword search, range search and k-nearest neighbor search operations in a privacy- preserving manner. All three types of queries are transformed into predicate-based search leveraging bucketization, locality sensitive hash- ing and homomorphic encryption techniques. The proposed framework is implemented using Hadoop MapReduce, and its efficiency and accu- racy are evaluated using publicly available real data sets. The imple- mentation results show that the proposed framework can effectively be used in moderate sized data sets and it is scalable for much larger data sets provided that the number of computers in the Hadoop cluster is increased. To the best of our knowledge, the proposed framework is the first privacy-preserving solution, in which three different types of search queries are effectively applied over encrypted data. Keywords:encrypted cloud data, multi-keyword search, k-nearest neigh- bor, range search, privacy preservation, scoring. ∗[email protected] [email protected] [email protected] 1 1 Introduction Recently, the need for reliably storing and efficiently processing massive amount of data experienced a sudden surge. The required computing and storage infrastructure to deal with the problem, however, is prohibitively expensive, thus most probably non-existent altogether for most small and medium-sized enterprises (SMEs).
    [Show full text]