Leakage Resilient IBE and IPE under the DLIN Assumption

Kaoru Kurosawa, Le Trieu Phong

Zvika Brakerski, Alex Lombardi, Gil Segev +1 more

Qiqi Lai, Feng-Hao Liu, Zhedong Wang

Toi Tomita, Wakaha Ogata, Kaoru Kurosawa +1 more

In this paper, we propose a new leakage-resilient identity-based encryption (IBE) scheme that is secure against chosen-ciphertext attacks (CCA) in the bounded memory leakage model. The security of our scheme is based on the external k-Linear assumption. It is the first CCA-secure leakage-resilient IBE scheme which does not depend on q-type assumptions. The leakage rate 1/10 is achieved under the XDLIN assumption (k=2).

Zvika Brakerski, Yael Tauman Kalai

Saisi Xiong, Yijian Zhang, Jie Chen

In this work, we present the first lattice-based construction of batched IBE in the standard model, whose security is proven under the succinct LWE assumption. Prior batched IBE schemes are only known either based on pairing-based assumptions or in the random oracle model. Moreover, our scheme is shown to be highly efficient, as the master public key, decryption key, and ciphertext are independent of the batch size B. Technically, we mainly rely on an insightful observation: batched IBE can be obtained solely from Inner-Product Encryption (IPE). To satisfy the efficiency requirements of batched IBE, we require an IPE scheme that owns two important features: decomposable key generation and compact components. Finally, we show how to construct such an IPE scheme from the well-known BGG+14 IPE scheme via careful modification.