System and Method for Confidentiality-Preserving Rank-Ordered Search

Abstract

A confidentiality preserving system and method for performing a rank-ordered search and retrieval of contents of a data collection. The system includes at least one computer system including a search and retrieval algorithm using term frequency and/or similar features for rank-ordering selective contents of the data collection, and enabling secure retrieval of the selective contents based on the rank-order. The search and retrieval algorithm includes a baseline algorithm, a partially server oriented algorithm, and/or a fully server oriented algorithm. The partially and/or fully server oriented algorithms use homomorphic and/or order preserving encryption for enabling search capability from a user other than an owner of the contents of the data collection. The confidentiality preserving method includes using term frequency for rank-ordering selective contents of the data collection, and retrieving the selective contents based on the rank-order.

What is claimed is: 
     
         1 . A confidentiality preserving system for performing a rank-ordered search and retrieval of contents of a data collection, the system comprising:
 at least one computer system including a search and retrieval algorithm using at least one of term frequency and similar features for rank-ordering selective contents of the data collection, and enabling secure retrieval of the selective contents based on the rank-order.   
     
     
         2 . A confidentiality preserving system according to  claim 1 , wherein the search and retrieval algorithm generates a relevance score for the rank-ordering based on at least one query. 
     
     
         3 . A confidentiality preserving system according to  claim 2 , wherein at least one of the data collection and query are encrypted. 
     
     
         4 . A confidentiality preserving system according to  claim 1 , wherein the data collection includes at least one of documents and multi-media content. 
     
     
         5 . A confidentiality preserving system according to  claim 1 , wherein the search and retrieval algorithm includes at least one of a baseline algorithm, a partially server oriented algorithm, and a fully server oriented algorithm. 
     
     
         6 . A confidentiality preserving system according to  claim 5 , wherein the baseline algorithm includes a pre-processing algorithm for building a secure term frequency table and an inverse data collection frequency table, and a search stage algorithm for the rank-ordering in response to a query. 
     
     
         7 . A confidentiality preserving system according to  claim 6 , wherein the pre-processing algorithm includes stemming of selective components of the contents of the data collection and mapping of the stemmed components in the term frequency table. 
     
     
         8 . A confidentiality preserving system according to  claim 7 , wherein the selective components are words, and the data collection contents are documents. 
     
     
         9 . A confidentiality preserving system according to  claim 6 , wherein the search stage algorithm includes stemming of a query term, searching of the term frequency table, generation of a relevance score, rank ordering of the selective contents of the data collection based on the relevance score, and retrieval of the selective contents of the data collection based on the rank order. 
     
     
         10 . A confidentiality preserving system according to  claim 6 , wherein the pre-processing and search stage algorithms are executed at a user site remote from a data center for storing the data collection. 
     
     
         11 . A confidentiality preserving system according to  claim 5 , wherein the partially server oriented algorithm includes performance of selective computations at a user site remote from a data center for storing the data collection. 
     
     
         12 . A confidentiality preserving system according to  claim 5 , wherein the partially server oriented algorithm includes at least one of building of a term frequency table and generation of a relevance score at a user site remote from a data center for storing the data collection. 
     
     
         13 . A confidentiality preserving system according to  claim 5 , wherein the fully server oriented algorithm includes building of a term frequency table at a user site and generation of a relevance score at a secure computing unit in a data center for storing the data collection. 
     
     
         14 . A confidentiality preserving system according to  claim 5 , wherein at least one of the partially and fully server oriented algorithms use at least one of homomorphic encryption and order-preserving encryption for enabling search capability from a user other than an owner of the contents of the data collection. 
     
     
         15 . A confidentiality preserving method for performing a rank-ordered search and retrieval of contents of a data collection, the method comprising:
 using at least one of term frequency and similar features for rank-ordering selective contents of the data collection; and   securely retrieving the selective contents based on the rank-order.   
     
     
         16 . A confidentiality preserving method according to  claim 15 , further comprising generating a relevance score for the rank-ordering based on at least one query. 
     
     
         17 . A confidentiality preserving method according to  claim 16 , further comprising encrypting at least one of the data collection and query. 
     
     
         18 . A confidentiality preserving method according to  claim 15 , wherein the data collection includes at least one of documents and multi-media content. 
     
     
         19 . A confidentiality preserving method according to  claim 15 , further comprising building a secure term frequency table and an inverse data collection frequency table by stemming of selective components of the contents of the data collection and mapping of the stemmed components in the term frequency table. 
     
     
         20 . A confidentiality preserving method according to  claim 15 , further comprising stemming of a query term, searching of a term frequency table, generation of a relevance score, rank ordering of the selective contents of the data collection based on the relevance score, and retrieval of the selective contents of the data collection based on the rank order.