(In)Security of Ring-LWE Under Partial Key Exposure

Journal of mathematical cryptology

article

Dana Dachman-Soled¹  Huijing Gong²  Mukul Kulkarni¹  Aria Shahverdi¹ 

[1] Department of Electrical and Computer Engineering and UMIACS, University of Maryland, 8125 Paint Branch Dr., College Park, MarylandUnited States of America;Department of Computer Science and UMIACS, University of Maryland, 8125 Paint Branch Dr., College Park, MarylandUnited States of America

关键词: Lattice-based cryptography;    leakage resilience;    Ring-LWE;    partial key exposure;   

DOI  :  10.1515/jmc-2020-0075

学科分类：社会科学、人文和艺术（综合）

来源: De Gruyter

【 摘 要 】

We initiate the study of partial key exposure in Ring-LWE (RLWE)-based cryptosystems. Specifically, we (1) Introduce the search and decision Leaky R-LWE assumptions (Leaky R-SLWE, Leaky R-DLWE), to formalize the hardness of search/decision RLWE under leakage of some fraction of coordinates of the NTT transform of the RLWE secret. (2) Present and implement an efficient key exposure attack that, given certain 1/4-fraction of the coordinates of the NTT transform of the RLWE secret, along with samples from the RLWE distribution, recovers the full RLWE secret for standard parameter settings. (3) Present a search-to-decision reduction for Leaky R-LWE for certain types of key exposure. (4) Propose applications to the security analysis of RLWE-based cryptosystems under partial key exposure.

【 授权许可】

CC BY|CC BY-NC-ND