Paper 2019/512

Tight Leakage-Resilient CCA-Security from Quasi-Adaptive Hash Proof System

Shuai Han, Shengli Liu, Lin Lyu, and Dawu Gu


We propose the concept of quasi-adaptive hash proof system (QAHPS), where the projection key is allowed to depend on the specific language for which hash values are computed. We formalize leakage-resilient(LR)-ardency for QAHPS by defining two statistical properties, including LR-<L_0,L_1>-universal and LR-<L_0,L_1>-key-switching. We provide a generic approach to tightly leakage-resilient CCA (LR-CCA) secure public-key encryption (PKE) from LR-ardent QAHPS. Our approach is reminiscent of the seminal work of Cramer and Shoup (Eurocrypt'02), and employ three QAHPS schemes, one for generating a uniform string to hide the plaintext, and the other two for proving the well-formedness of the ciphertext. The LR-ardency of QAHPS makes possible the tight LR-CCA security. We give instantiations based on the standard k-Linear (k-LIN) assumptions over asymmetric and symmetric pairing groups, respectively, and obtain fully compact PKE with tight LR-CCA security. The security loss is O(log Q_e) where Q_e denotes the number of encryption queries. Specifically, our tightly LR-CCA secure PKE instantiation from SXDH has only 4 group elements in the public key and 7 group elements in the ciphertext, thus is the most efficient one.

Note: Minor changes for descriptions.

Available format(s)
Public-key cryptography
Publication info
A major revision of an IACR publication in Crypto 2019
public-key encryptionleakage-resilienceCCA securitytight security reductionhash proof system
Contact author(s)
dalen17 @ sjtu edu cn
slliu @ sjtu edu cn
lvlin @ sjtu edu cn
dwgu @ sjtu edu cn
2019-05-23: last of 2 revisions
2019-05-20: received
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Creative Commons Attribution


      author = {Shuai Han and Shengli Liu and Lin Lyu and Dawu Gu},
      title = {Tight Leakage-Resilient CCA-Security from Quasi-Adaptive Hash Proof System},
      howpublished = {Cryptology ePrint Archive, Paper 2019/512},
      year = {2019},
      note = {\url{}},
      url = {}
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