### Public Key Broadcast Encryption with Low Number of Keys and Constant Decryption Time (Version 2)

Yi-Ru Liu and Wen-Guey Tzeng

##### Abstract

In this paper we propose two public key BE schemes that have efficient complexity measures. The first scheme, called the PBE-PI scheme, has $O(r)$ header size, $O(1)$ public keys and $O(\log N)$ private keys per user, where $r$ is the number of revoked users. This is the first public key BE scheme that has both public and private keys under $O(\log N)$ while the header size is $O(r)$. These complexity measures match those of efficient secret key BE schemes. \par Our second scheme, called the PBE-SD-PI scheme, has $O(r)$ header size, $O(1)$ public key and $O(\log N)$ private keys per user also. However, its decryption time is remarkably $O(1)$. This is the first public key BE scheme that has $O(1)$ decryption time while other complexity measures are kept low. Overall, this is the most efficient public key BE scheme up to now. \par Our basic schemes are one-way secure against {\em full collusion of revoked users} in the random oracle model under the BDH assumption. We modify our schemes to have indistinguishably security against adaptive chosen ciphertext attacks.

Note: Improved version

Available format(s)
Category
Public-key cryptography
Publication info
Published elsewhere. broadcast encryption
Contact author(s)
wgtzeng @ cs nctu edu tw
History
2008-04-01: revised
See all versions
Short URL
https://ia.cr/2007/167

CC BY

BibTeX

@misc{cryptoeprint:2007/167,
author = {Yi-Ru Liu and Wen-Guey Tzeng},
title = {Public Key Broadcast Encryption with Low Number of Keys and Constant Decryption Time (Version 2)},
howpublished = {Cryptology ePrint Archive, Paper 2007/167},
year = {2007},
note = {\url{https://eprint.iacr.org/2007/167}},
url = {https://eprint.iacr.org/2007/167}
}

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