Identity-Based Matchmaking Encryption from Standard Assumptions

• Published in: Advances in Cryptology - ASIACRYPT 2022 Vol. 13793; pp. 394 - 422
• Main Authors: Chen, Jie, Li, Yu, Wen, Jinming, Weng, Jian
• Format: Book Chapter
• Language: English
• Published: Switzerland Springer 2023; Springer Nature Switzerland
• Series: Lecture Notes in Computer Science
• Subjects: Identity-based encryption; Matchmaking encryption; Standard assumptions; Standard model
• ISBN: 3031229681; 9783031229688
• ISSN: 0302-9743; 1611-3349
• DOI: 10.1007/978-3-031-22969-5_14

In this work, we propose the first identity-based matchmaking encryption (IB-ME) scheme under the standard assumptions in the standard model. This scheme is proven to be secure under the symmetric external Diffie-Hellman (SXDH) assumption in prime order bilinear pairing groups. In our IB-ME scheme, all parameters have constant number of group elements and are simpler than those of previous constructions. Previous works are either in the random oracle model or based on the q-type assumptions, while ours is built directly in the standard model and based on static assumptions, and does not rely on other crypto tools. More concretely, our IB-ME scheme is constructed from a variant of two-level anonymous IBE. We observed that this two-level IBE with anonymity and unforgeability satisfies the same functionality of IB-ME, and its security properties cleverly meet the two requirements of IB-ME (Privacy and Authenticity). The privacy property of IB-ME relies on the anonymity of this two-level IBE, while the authenticity property is corresponding to the unforgeability in the 2nd level. This variant of two-level IBE is built from dual pairing vector spaces, and both security reductions rely on dual system encryption.