Cryptology ePrint Archive: Report 2020/126

Public-Key Puncturable Encryption: Modular and Compact Constructions

Shi-Feng Sun and Amin Sakzad and Ron Steinfeld and Joseph Liu and Dawu Gu

Abstract: We revisit the method of designing public-key puncturable encryption schemes and present a generic conversion by leveraging the techniques of distributed key-distribution and revocable encryption. In particular, we first introduce a refined version of identity-based revocable encryption, named key-homomorphic identity-based revocable key encapsulation mechanism with extended correctness. Then, we propose a generic construction of puncturable key encapsulation mechanism from the former by merging the idea of distributed key-distribution. Compared to the state-of-the-art, our generic construction supports unbounded number of punctures and multiple tags per message, thus achieving more fine-grained revocation of decryption capability. Further, it does not rely on random oracles, not suffer from non-negligible correctness error, and results in a variety of efficient schemes with distinct features. More precisely, we obtain the first scheme with very compact ciphertexts in the standard model, and the first scheme with support for both unbounded size of tags per ciphertext and unbounded punctures as well as constant-time puncture operation. Moreover, we get a comparable scheme proven secure under the standard DBDH assumption, which enjoys both faster encryption and decryption than previous works based on the same assumption, especially when the number of tags associated with the ciphertext is large.

Category / Keywords: public-key cryptography / Functional Encryption, Puncturable Encryption, Forward Security

Original Publication (with minor differences): IACR-PKC-2020

Date: received 5 Feb 2020, last revised 5 Feb 2020

Contact author: shifeng sun at monash edu,amin sakzad@monash edu,ron steinfeld@monash edu,joseph liu@monash edu,dwgu@sjtu edu cn

Available format(s): PDF | BibTeX Citation

Version: 20200206:144947 (All versions of this report)

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