International Association for Cryptologic Research

International Association
for Cryptologic Research


Paper: Ring-based Identity Based Encryption – Asymptotically Shorter MPK and Tighter Security

Parhat Abla
Feng-Hao Liu
Han Wang
Zhedong Wang
DOI: 10.1007/978-3-030-90456-2_6
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Abstract: This work constructs an identity based encryption from the ring learning with errors assumption (RLWE), with shorter master public keys and tighter security analysis. To achieve this, we develop three new methods: (1) a new homomorphic equality test method using nice algebraic structures of the rings, (2) a new family of hash functions with natural homomorphic evaluation algorithms, and (3) a new insight for tighter reduction analyses. These methods can be used to improve other important cryptographic tasks, and thus are of general interests. Particularly, our homomorphic equality test method can derive a new method for packing/unpacking GSW-style encodings, showing a new non-trivial advantage of RLWE over the plain LWE. Moreover, our new insight for tighter analyses can improve the analyses of all the currently known partition-based IBE designs, achieving the best of the both from prior analytical frameworks of Waters (Eurocrypt ’05) and Bellare and Ristenpart (Eurocrypt ’09).
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  title={Ring-based Identity Based Encryption – Asymptotically Shorter MPK and Tighter Security},
  booktitle={Theory of Cryptography;19th International Conference},
  author={Parhat Abla and Feng-Hao Liu and Han Wang and Zhedong Wang},