World's first: Method for integrating and analyzing encrypted data to accelerate data analysis of marketing information
Presented at ACM CCS, the premier international conference on security

Tokyo -November 27, 2023 - NTT Corporation (NTT) has developed a method for combining multiple data sets and performing GROUP-BY operations, which groups rows and computes statistical values for each group,in secure computation that analyzes data while keeping it encrypted. The method consists of two parts. In the data integration part, we achieved the world's highest speed of 3.95 times the conventional measured value, and in the GROUP-BY operation part, we realized the calculation of the median value, which is an important statistical value, for the first time in the world. By using this method, it is possible to integrate and analyze data from multiple organizations by secure computation in less time and with a wider variety of statistical values, and the range of privacy-preserving data utilization by secure computation is expanded. This result has already been implemented as an internal arithmetic in the "Secihi" service provided by NTT Communications Corporation (NTT Com), and customers can use the analysis using this result.
　These results was presented at the 30th ACM Conference on Computer and Communications Security (ACM CCS 2023), the premier international conference in the field of security, held in Copenhagen, Denmark, from November 26 to 30, 2023.

1. Background of the study

In recent years, as the use of data has expanded, the issue has been how to ensure safety and security when expanding the use of information about individuals and sensitive data. In response to this challenge, NTT has been researching a secure computation that calculates the analysis results while encrypting the data, without ever revealing the values during the computation. Theoretical research has proven that secure computation can achieve arbitrary processing, but only a limited number of processes can be performed in a realistic time. One of the promising applications of secure computation is the analysis of data from organizations in different industries. In order to analyze a large amount of data and many types of data, it was hoped that efficient secure computation for various analyses could be realized.

2. Results of research

With this technology, a series of data processing (Figure 1), in which data brought in by multiple organizations are combined in encrypted form to calculate statistical values (GROUP-BY operations), can now be performed more efficiently on a wide variety of statistical values. Even for data that includes extreme values such as credit usage, Company A, which sell music data, and Credit Card Company B perform analysis (grouping and aggregating) focusing on the relationship between favorite music and credit card usage. The data of both companies is gathered without revealing it to anyone, and the statistics of credit usage for each genre of favorite music can be calculated.

Figure 1 Processing Realized by the Developed Technology

On the other hand, the grouping and aggregating algorithm developed by NTT can be used for the first time in the world to calculate important statistics, such as medians and percentiles, that are less affected by extreme values, enabling analysis that captures the characteristics of the data (Figure 2). In addition, the newly developed data combination algorithm has achieved the world's highest speed of 3.95 times the measured value compared to the conventional technology. Using these algorithms, we obtained an experimental result that completed a series of processes in 9 seconds, from combining 1 million customer data to calculating 5 kinds of statistics (Count, Sum, Maximum, Minimum, and Median) of credit usage for each genre of favorite music.

Figure 2 Usage Image of the Developed Technology

3. Point of technology

NTT has developed a new method for integrating and aggregating data in a way that is different from conventional technologies. There are two main points.

4. Outlook

This result is implemented in the service "Secihi" provided by NTT Com, which contributes to the secure statistical analysis of data brought by multiple organizations through the service. In the future, we will further expand operations to realize a wider range of database processing.

< Reference >

NTT Communications Corporation Secure Computation Service (Secihi)
https://www.ntt.com/business/services/secihi.html

^※Secihi is a trademark of NTT Communications Corporation.

About NTT

NTT contributes to a sustainable society through the power of innovation. We are a leading global technology company providing services to consumers and business as a mobile operator, infrastructure, networks, applications, and consulting provider. Our offerings include digital business consulting, managed application services, workplace and cloud solutions, data center and edge computing, all supported by our deep global industry expertise. We are over $95B in revenue and 330,000 employees, with $3.6B in annual R&D investments. Our operations span across 80+ countries and regions, allowing us to serve clients in over 190 of them. We serve over 75% of Fortune Global 100 companies, thousands of other enterprise and government clients and millions of consumers.