Cryptology ePrint Archive: Report 2017/408

Combinatorial Subset Difference Public Key Broadcast Encryption Scheme for Secure Multicast

Jihye Kim and Jiwon Lee and Seunghwa Lee and Hyunok Oh

Abstract: Public key broadcast encryption is a cryptographic method to securely transmit a message from anyone to a group of receivers such that only privileged users can decrypt it. A secure multicast system allows a user to send a message to a dynamically changing group of users. The secure multicast can be realized by the broadcast encryption.

In this paper, we propose a novel combinatorial subset difference (CSD) public key broadcast encryption covering method which allows a generalized subset difference representation in which wildcards can be placed at any position. The proposed CSD is suitable for the secure multicast while minimizing the header size compared with the existing public key broadcast encryption schemes without sacrificing key storage and encryption/decryption performance.

Experimental results show that the proposed CSD scheme not only reduces the ciphertext header size by 17% and 31% but also improves encryption performance (per subset) by 6 and 1.3 times, and decryption performance by 10 and 19 times compared with existing efficient subset difference (SD) and interval schemes, respectively. Furthermore, especially for subsets represented in a non-hierarchical manner, the proposed CSD reduces the number of subsets by a factor of 1000 times compared with SD and interval approaches. We prove the semantic security of our proposed CSD scheme under the l-BDHE assumption without the random oracle model.

Category / Keywords: public-key cryptography / broadcast encryption, secure multicast, wildcard, subset difference, public key

Original Publication (with minor differences): ACM/SIGAPP Symposium on Applied Computing, 2018

Date: received 11 May 2017, last revised 13 Nov 2019

Contact author: jihyek at kookmin ac kr,jiwonlee@hanyang ac kr,ttyhgo@kookmin ac kr,hoh@hanyang ac kr

Available format(s): PDF | BibTeX Citation

Version: 20191114:044557 (All versions of this report)

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