Study on multi-user homomorphic functional signatures

2019 Fiscal Year Final Research Report

• Project/Area Number: 16K16068
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Information security
• Research Institution: National Institute of Advanced Industrial Science and Technology
• Principal Investigator: Yamada Shota 国立研究開発法人産業技術総合研究所, 情報・人間工学領域, 研究員 (70750834)
• Project Period (FY): 2016-04-01 – 2020-03-31
• Keywords: 電子署名 / 準同型署名 / 属性ベース署名 / グループ署名 / 格子暗号

Outline of Final Research Achievements

Homomorphic signature is an advanced form of conventional digital signatures where one can homomorphically evaluate on the signatures while preserving authenticity and privacy of data. In homomorphic signatures, there are two limitations. Firstly, in homomorphic signatures, there is no mechanism to control the signing capability of the signing entity. Secondly, homomorphic evaluation on signatures is available only when the signatures are generated by the same entity. In this research project, we tried to overcome these limitations and obtained new cryptographic schemes such as attribute-based signature, which is an advanced form of signature that allows access control over signing entities in the multi-use settings, as well as group signatures and non-interactive zero-knowledge protocols as partial results.

Free Research Field

暗号理論

Academic Significance and Societal Importance of the Research Achievements

本研究では，目的としていた「多ユーザ関数型準同型署名」の設計を目指して研究し，目標に近い技術である属性ベース署名やグループ署名の設計を提案した．グループ署名方式は，シンプルなアクセス制御機構と，追跡可能性を保持した高機能電子署名技術で，提案方式は初めての量子コンピュータに対しても安全な方式である．また，研究の過程で新たな暗号理論的テクニックを発見し，複数の新たな高機能暗号技術を提案した．これは今後の当該分野の理論的発展および真に実用的な高機能暗号技術の実社会への普及に向けて，一定程度の意義があるものと考えられる．