As quantum computers become more practical, Hitachi has developed a high-speed searchable encryption technology based on quantum-resistant public key cryptography known as lattice cryptography to address the risk of decryption that conventional encryption technologies pose. This technology can search large amounts of data encrypted and stored on cloud servers in the encrypted state 10 times faster than conventional quantum-resistant public key searchable encryption technology. In addition, statistical processing of encrypted data can also be safely performed. This will greatly expand the scope of data utilization, for example, for medical data analysis, while ensuring data security.
Hitachi aims to apply this technology in a wide range of fields, including healthcare, the public sector, and finance, and will continue to contribute to improving customer data protection and utilization.
In recent years, the use of services that collect and analyze personal and confidential information on cloud servers has expanded. However, there are concerns that the advancement of practical use of quantum computers will increase the risk of conventional encryption techniques being cracked. For this reason, there is a demand for new encryption techniques that can withstand attacks by quantum computers. However, conventional post-quantum encryption techniques impose a high computational load, making it difficult to efficiently search large amounts of data. In addition, there is a risk of privacy leaks from statistical processing using search results.
Hitachi has therefore developed a high-speed searchable encryption technology based on lattice cryptography, a quantum-resistant public key cryptography technology, and a privacy-preserving secret statistical calculation technology that uses it. The features of the developed technology are as follows:
1. Achieving both high security and high-speed searches by reducing the number of vector dimensions
We conducted a detailed security analysis of the conventional method and succeeded in reducing the number of dimensions of the vector used in the search process without compromising security. As a result, we achieved searches 10 times faster than conventional lattice cryptography, enabling efficient searches of large amounts of data.
2. Securing data extraction and private statistical calculation technology
From the perspective of privacy protection, there is a concern that when the amount of data handled is small, the original data may be inferred from the statistics. Therefore, in order to achieve secure statistical calculations, it has been a challenge to extract a certain amount of data suitable for statistical processing. Hitachi has developed a technology that uses secret sharing technology*4 to convert search results into data suitable for statistical processing only when a certain number of results have been collected. Furthermore, by combining this with homomorphic encryption technology*5, it has been possible to calculate statistics in an encrypted state. This will expand the scope of data utilization, for example, by analyzing medical data while protecting patient privacy.
Hitachi will continue to conduct research and development of this technology with the aim of commercializing it in a variety of fields, including healthcare, the public sector, and finance, and will contribute to the realization of safe and highly efficient data utilization through the development of security technology suited to the era of quantum computers.
SOURCE: PRTimes
