学術論文誌

More Efficient Adaptively Secure Latticebased IBE with Equality Test in the Standard Model
 著者
 K. Asano, K. Emura, and A. Takayasu
 雑誌名
 IEICE Transactions on Fundamentals
 出版社
 IEICE
 発行年
 2024
To appear.Abstract
Identitybased encryption with equality test (IBEET) is a variant of identitybased encryption (IBE), in which any user with trapdoors can check whether two ciphertexts are encryption of the same plaintext. Although several latticebased IBEET schemes have been proposed, they have drawbacks in either security or efficiency. Specifically, most IBEET schemes only satisfy selective security, while public keys of adaptively secure schemes in the standard model consist of matrices whose numbers are linear in the security parameter. In other words, known latticebased IBEET schemes perform poorly compared to the stateoftheart latticebased IBE schemes (without equality test). In this paper, we propose a semigeneric construction of CCAsecure latticebased IBEET from a certain class of latticebased IBE schemes. As a result, we obtain the first latticebased IBEET schemes with adaptive security and CCA security in the standard model without sacrificing efficiency. This is because, our semigeneric construction can use several stateoftheart latticebased IBE schemes as underlying schemes, e.g. Yamada's IBE scheme (CRYPTO'17).